A  TEXT-BOOK  OF  CHEMISTRY. 
HILL. 


A   TEXT-BOOK 


OF 


CHEMISTRY 


FOR  STUDENTS  OF  MEDICINE, 
PHARMACY,  AND   DENTISTRY 


BY 

EDWARD  CURTIS  fJILL,  M.S.,  M.D. 

MEDICAL    ANALYST    AND    MICROSCOPIST ;     PROFESSOR    OF    CHEMISTRY    AND    METALLURGY 

IN     THE     COLORADO      COLLEGE     OF      DENTAL      SURGERY;      PROFESSOR     OF 

CHEMISTRY    AND    TOXICOLOGY    IN    THE     DENVER    AND    GROSS 

COLLEGE  OF  MEDICINE,  UNIVERSITY    OF  DENVER. 


WITH   SEVENTY-EIGHT   ILLUSTRATIONS,  INCLUDING  NINE 
FULL-PAGE   HALF-TONE  AND  COLORED   PLATES 


PHILADELPHIA 

F.  A.  DAVIS  COMPANY,  PUBLISHERS 

1903 


COPYRIGHT,  1903, 

BY 

F.  A.  DAVIS  COMPANY. 
[Registered  at  Stationers'  Hall,  London,  Eng.] 


Philadelphia,  Pa.,  U.  S.  A.  : 

The  Medical  Bulletin  Printing-house, 

1914-16  Cherry  Street. 


TO 

WILLIAM  HARMON  BUCHTEL,  M.D.,  LLD, 

THIS  VOLUME  IS  INSCRIBED  AS  A 
TRIBUTE    OF    GRATEFUL    ESTEEM 


4751 


PREFACE. 


THE  present  volume  has  been  built  up  from  lectures  for 
ten  years  in  medical  and  dental  schools.  The  author  has  tried 
to  make  facts  clear  and  simple,  and  has  utilized  topic  gen- 
eralizations as  much  as  practicable.  The  free  use  of  formulas 
in  the  text  is  intended  to  familiarize  students  with  chemic 
nomenclature  and  notation.  It  is  hoped  that  the  book  will  be 
a  help  to  students  of  medicine,  pharmacy,  and  dentistry. 

For  material,  the  writer  is  particularly  indebted  to  the 
following  authorities:  Bartley,  Sadtler  and  Trimble,  Novy, 
Hall,  Bunge,  Muter,  Scoville,  Mitchell,  Rockwood,  Wolf,  Long, 
Taylor,  Tanner,  Simon,  Leffmann,  Gage,  Draper,  Purdy,  Rohe, 
Neubauer  and  Vogel,  and  the  "American  Text-book  of  Phys- 
iology." He  would  also  express  his  obligations  to  the  publishers 
for  the  care  and  liberality  they  have  shown  in  the  mechanic 
make-up  of  the  book. 


(v) 


CONTENTS. 


PAGE 

MEDICAL  PHYSICS  1-69 

General  Definitions  and  Distinctions 1 

General  Properties  of  Matter 2 

Special  Properties  of  Matter: 

Solids  8 

Liquids 10 

Gases    16 

Heat 19 

Electricity 42 

Magnetism  and  Electromagnetism 53 

Crystallography    58 

Osmosis  and  Dialysis 61 

Sound     63 

Questions    66 

CHEMIC  PHILOSOPHY    70-88 

Elements  70 

Atoms  and  their  Properties 72 

Atomicity   73 

Atomic  Weights   73 

Polarity    74 

Valence 75 

Molecules  and  Formulas 77 

Acids,  Bases,  and  Salts 80 

Chemic  Reactions  and  Equations 84 

Stoechiometry    85 

The  Periodic  Law 87 

Questions    87 

INORGANIC  CHEMISTRY    89-188 

Metals: 

Discovery  and  Derivation 89 

Ordinary  Sources  in  Nature 90 

Combination    90 

Extraction    91 

Physic  Properties  95 

Chemic  Properties   99 

Physiologic  Properties    103 

Uses   104 

Metallic  Groups    , •  107 

Alloys    107 

Metalloids 113 

Oxids    131 

Inorganic  Acids    144 

Hydroxids     151 

Salts 154 

Questions 183 

(vii) 


Viii  CONTENTS. 

PAGE 

THE  CARBON  COMPOUNDS 189-255 

Hydrocarbons    191 

Hydrocarbon  Derivatives  200 

Alkyl  Salts 203 

Alcohols    204 

Ethers    208 

Aldehyds  210 

Acetals  and  Ketones 212 

Organic  Acids   213 

Fats  and  Fixed  Oils 219 

Soaps   222 

Carbohydrates 224 

Glucosids    230 

Vegetable  Coloring  Matters 232 

Unclassified  Bitter  Principles 234 

Phenols    235 

Nitro-derivatives  and  Thio-compounds 236 

Amido-phenols     237 

Compound  Ammonias  238 

Pyridins,  Azo  and  Diazo  Compounds,  Hydrazins 240 

Nitrils  and  Carbylamins 241 

Alkaloids   241 

Proteins     246 

Ferments . 251 

Questions 254 

ANALYSIS  256-293 

Qualitative  Analysis: 

General  Directions   256 

Finding  the  Metal 259 

Finding  the  Acid,  or  Radical 263 

Pyrology  269 

Quantitative  Analysis 273 

Special  Methods  and  Apparatus 279 

Microchemic  Tests   281 

Nitrometry  282 

Pharmaceutic  Assays    283 

Ultimate  Analysis   284 

Finding  the  Molecular  Weight 285 

Analysis  of  Amalgam  Alloys 286 

Refining  cf  Gold 287 

Identification  of  Principal  Fixed  Oils 288 

Detection  of  Common  Sugars 289 

Color-reactions  of  Common  Alkaloids 290 

Questions 292 

INCOMPATIBILITY    294-306 

•General  Rules 294 

Summary  of  Solubilities  of  Medicinal  Salts 295 

Compound  Solvents  in  Aqueous  Solution 297 

Gas-formation :    Effervescence,  Explosion,  Combustion 299 

Poisonous  Reactions   300 

Special  Incompatibilities    300 

Liquefaction  on  Trituration 302 

Chemic  Decomposition  on  Trituration 302 


CONTENTS.  ix 

INCOMPATIBILITY  (Concluded).  PAGE 

Incompatibilities  of  Water 302 

Prescriptions    303 

Action  of  Air,  Light,  and  Atmospheric  Heat 303 

Practical  Exercises 305 

SANITARY  CHEMISTRY   307-335 

The  Air  307 

Water    309 

Purification    312 

Sanitary  Analysis 313 

Poisonous  Metals  318 

Adulterants  and  Sophisticants : 

Food 319 

Drug  Impurities    325 

Antiseptics  and  Disinfectants 326 

Questions    334 

TOXICOLOGY 336-365 

Definition    336 

Acute  Poisoning  336 

Antidotes  in  General 342 

Corrosives  343 

Irritants : 

Mineral    345 

Vegetable    348 

Animal     349 

Gases    350 

Neurotics : 

Narcotics    351 

Depressants 354 

Convulsants    , 356 

Chronic  Poisoning    357 

Poisonous  Bites  and  Stings 363 

Questions    364 

PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY 366-417 

Chemic  Composition  of  the  Human  Body 366 

Bones   371 

Teeth    372 

Muscle   373 

Nerve-substance,  Epidermal  Structures,  Connective  Tissues .  .  .   374 

Cartilage ;   the  Viscera 375 

The  Blood  375 

Secretions    380 

Excretions     391 

Animal  Functions 396 

Digestion     396 

Absorption   398 

Metabolism 400 

Respiration 403 

Food  and  Diet 404 

Animal  Foods    407 

Vegetable  Foods  408 

Cooking  .- 409 

Beverages 410 


X  CONTENTS. 

PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY  (Concluded).  PAGE 

Autotoxemia 411 

Infection  and  Immunity 412 

Questions    .  416 

CLINIC  CHEMISTRY  418-485 

Gastric  Juice  418 

Practical  Quantitative  Analysis .  .  .  420 

Milk 421 

The  Urine  425 

General  Properties   426 

Normal  Constituents  434 

Abnormal  Conditions    446 

Microchemistry   459 

Crystals     460 

Granules    464 

Casts    465 

Cells   470 

Bacteria     475 

Differentiation  of  Nephritides 477 

Diagnosis  of  Non-urinary  Diseases 478 

Urinary  Calculi 483 

Questions    484 

APPENDIX 487-510 

Solubility  of  Common  Drugs 489 

Arithmetic  Constants 495 

Equations  of  Manufacturing  Chemistry 496 

Ores,  Rocks,  and  Minerals 500 

Popular  and  Alchemic  Names 502 


LIST  OF  ILLUSTRATIONS. 


FIG.  PAGE 

1.  Analytic  Balance  6 

2.  Capillary  Attraction  and  Repulsion 11 

3.  Hydrostatic  Balance 13 

4.  Picnometer 14 

5.  Hydrometer 14 

6.  Westphal  Specific  Gravity  Balance 15 

7.  Mercurial  Barometer    17 

8.  Comparison  of  Thermometer  Scales 22 

9.  Apparatus  for  Distillation 27 

10.  Radiometer    32 

11.  Lenses 35 

12.  The  Laurent  Shadow  Polarizing  Saccharimeter 41 

13.  Electrostatic  Machine    44 

14.  A  Galvanic  Cell 46 

15.  Faure's  Modification  of  the  Plante  Storage  Cell 47 

16.  Horizontal  Mil-am-meter 48 

17.  Electrolysis    49 

18.  Telephone     56 

19.  Systems  of  Crystallization 59 

20.  Sectional  View  of  Blast  Furnace 94 

21.  Apparatus  for  Determining  the  Melting-point  of  a  Solid 112 

22.  Preparation  of  Hydrogen 114 

23.  Preparation  of  Chlorin 116 

24.  Sublimation   of   Sulphur 122 

25.  Preparation  of  Nitrogen 124 

26.  Preparation  of  Sulphuric  Acid 147 

27.  Revolving  Black-Ash  Furnace 166 

28.  Interior  of  Pottery  Kiln 175 

29.  Manufacture  of  Coal-gas 195 

30.  Quick  Vinegar  Process 214 

31.  Lard,  Crystallized  from  Chloroform 220 

32.  Human  Fat,  Crystallized  from  Chloroform 221 

33.  Soap  Coppers    223 

34.  Vacuum  Pan 228 

35.  Apparatus  for  Solution  (Rockwood) 257 

36.  Apparatus  for  Evaporation  (Rockwood) 257 

37.  Apparatus  for  Filtration  (Rockwood) 258 

38.  Apparatus  for  Fusion  (Rockwood) 258 

39.  Bunsen  Flame 270 

40.  Oxidizing  Blow-pipe  Flame  (Light  Blue) 271 

41.  Reducing  Blow-pipe"  Flame   (Yellow) 271 

42.  Apparatus  for  Detection  of  Minute  Amount  of  Arsenic 280 

43.  Nitrometer     283 

44.  Victor  Meyer  Apparatus 286 

45.  Dental  Furnace    292 

46.  Cylinder  for  Nesslerization 316 

47.  Hemin  Crystals   379 

48.  Human  Milk  and  Colostrum 386 

49.  Spermatozoa  and  Bottcher's  Crystals 389 

(xi) 


xii  ILLUSTRATIONS. 

FIG.  PAGE 

50.  Reichert's  Water-calorimeter  402 

51.  Feser's  Lactoscope    423 

52.  Purdy's  Electric  Centrifuge 426 

53.  Squibb's  Urinometer 433 

54.  Doremus  Ureometer  438 

55.  Kjeldahl  Method  ......'.!'!..  440 

56.  Esbach's  Albuminometer  449 

57.  Sodium  Urate  Crystals 460 

58.  Cystin  Crystals    461 

59.  Calcium  Oxalate  Crystals 462 

60.  Hippuric  Acid  Crystals 463 

61.  Narrow  Hyaline  Casts 466 

62.  Epithelial  Casts  467 

63.  Granular  Casts 468 

64.  Waxy  Casts   468 

65.  False  Casts   469 

66.  Pus-corpuscles    470 

67.  Normal  Blood-corpuscles 471 

68.  Urinary  Epithelia   472 

69.  Micrococcus  Ureae  .   475 


LIST  OF  PLATES. 


PLATE  PAGE 

I.  Starches  (Bartley)   226 

II.  Inorganic  Poisons  280 

III.  Organic  Poisons 282 

IV.  Absorption-spectra  (Rockwood)    380 

V.  Vogel's  Scale  of  Urine  Tints 426 

VI.  Crystals  of  Phenylglucosazone  (after  v.  JakscJi) 452 

VII.  Urinary  Crystals    460 

VIII.  Tubercle  Bacilli  in  Urinary  Sediment  (after  v.  Jaksch) 476 

IX.  Characteristic  Microscopic  Sediments 478 


MEDICAL  PHYSICS. 


GENERAL  DEFINITIONS  AND  DISTINCTIONS. 

EVERYTHING  about  us  consists  of  matter.  Matter  is  per- 
ceived by  the  senses,  especially  by  sight;  but  there  are  also 
many  invisible  substances.  Air,  for  instance,  though  trans- 
parent and  invisible,  is  as  material  in  its  nature  as  is  iron  or 
salt. 

Any  appreciable  change  in  matter  is  termed  a  phenom- 
enon. Natural,  or  physic,  science  is  classified  knowledge  con- 
cerning matter  and  its  phenomena. 

Chemistry  is  that  branch  of  natural  science  which  treats 
of  the  intimate  composition  of  matter,  the  changes  in  com- 
position, and  the  principles  governing  such  changes.  It  is, 
therefore,  the  most  rational  of  studies,  since  it  seeks  to  find 
an  ultimate  reason  for  every  natural  phenomenon.  As  an  art, 
chemistry  has  discovered  and  prepared  the  greater  number  of 
medicinal  agents  now  in  use.  A  practical  knowledge  of  chem- 
istry is  as  essential  to  the  pharmacist  and  physician  as  is  me- 
chanics to  the  engineer  or  draughting  to  the  architect. 

Physics  differs  from  chemistry  in  that  it  treats  of  the  forces 
and  motions  of  matter  in  the  mass  rather  than  its  final  com- 
ponents. The  two  sciences  are,  however,  closely  related,  and 
an  elementary  knowledge  of  physics,  or  natural  philosophy,  is 
essential  to  the  understanding  of  chemistry. 

In  consonance  with  the  definitions  given  above,  a  chemic 
change  is  one  in  which  the  composition  of  a  substance  is  per- 
manently altered;  a  physic  change  affects  only  the  form,  and 
that  temporarily.  The  conversion  of  water  into  steam  or  ice 
is  an  example  of  a  physic  change.  The  union  of  water  with 
lime,  forming  lime-water,  a  new  substance,  is  an  illustration 
of  chemic  change. 

Experiment. — Heat  1  gm.  of  iron  filings  for  ten  minutes;  then 
weigh  again.  Explain  change  in  color  and  increase  in  weight.  Would 
these  changes  have  taken  place  had  the  metal  been  heated  in  a  vacuum  ? 

Experiment. — Mix  equal  parts  of  sulphur  and  iron  filings,  moisten 
with  water,  and  set  aside.  In  a  few  minutes  the  mixture  becomes  hot 
and  changes  to  a  black  mass  of  ferrous  sulphid. 

(i) 


2  MEDICAL  PHYSICS. 

Experiment. — Mix  intimately,  but  cautiously,  with  a  spatula  a 
teaspoonful  of  powdered  chlorate  of  potassium  with  twice  as  much 
cane-sugar.  Place  the  powder  in  a  convenient  vessel  and  drop  on  a 
few  minims  of  strong  sulphuric  acid.  A  bluish  flame  is  evoked,  the 
sugar  is  charred,  and  a  suffocating  gas  is  evolved. 


GENERAL  PROPERTIES  OF  MATTER. 

The  general  or  essential  properties  or  qualities  inherent 
to  all  matter  are  the  following:  Indestructibility,  extension, 
attraction,  weight,  divisibility,  impenetrability,  porosity,  com- 
pressibility, elasticity,  inertia,  and  mobility. 

Indestructibility. — No  particle  of  matter  was  ever  created 
or  destroyed  by  human  or  natural  agencies.  Everything  is 
apparently  subject  to  complete  destruction  in  its  final  decay, 
but  in  reality  there  is  only  chemic  change  and  new  combina- 
tions. The  vegetation  of  by-gone  ages  becomes  coal;  this  is 
consumed  into  ashes  and  gases  in  the  fire  which  chemic  change 
produces  and  maintains;  living  plants  live  and  grow  by  ab- 
sorbing the  ashes  through  their  roots  and  the  gases  through 
their  stems  and  leaves;  and  thus  the  round  of  transformation 
goes  on.  Water  can  be  resolved  by  electricity  into  its  com- 
ponent gases,  hydrogen  and  oxygen,  the  sum  of  whose  weights 
in  any  given  case  is  always  equal  to  that  of  the  quantity  of 
the  liquid  decomposed.  The  great  fact  of  the  indestructibility 
of  matter  is  the  foundation  of  modern  natural  science. 

Extension. — Extension  is  that  property  of  matter  by  virtue 
of  which  it  occupies  space.  All  forms  of  matter,  even  though 
invisible,  possess  this  property.  The  amount  of  space  occu- 
pied by  any  given  portion  of  matter  is  termed  its  volume,  which 
implies  all  three  dimensions:  length,  breadth,  and  thickness. 
Extension  in  two  directions  is  called  area,  or  square  measure; 
in  one  direction,  length,  or  linear  measure.  Mass  signifies  the 
quantity  of  matter  in  a  body,  and  is  equivalent  to  the  product 
of  the  relative  density  or  compactness  of  the  substance  by  its 
volume.  The  term  mass,  however,  is  not  identic  with  weight; 
mass  is  not  affected  by  gravity,  but  implies  resistance  to  mo- 
tion. Platinum  has  a  density  of  about  1400  pounds  per  cubic 
foot;  hence  a  mass  6  inches  cube  weighs  1/8  of  1400,  or  175 
pounds. 

The  system  of  measurements  employed  by  scientists  in 
all  parts  of  the  world  is  the  metric  system.  It  is  a  decimal 
method,  the  unit  of  which  is  the  meter,  equivalent  to  39.37 
inches.  A  cube  of  water  Vioo  meter  on  each  side  (Vioooooo 
cubic  meter),  weighed  at  4°  C.,  is  the  unit  of  weight,  and  is 


GENERAL  PROPERTIES  OF  MATTER.  3 

called  a  gram,  being  equal  to  15.43  Troy  grains.  The  unit  of 
capacity  is  the  liter,  represented  by  a  cube  Vio  meter  in  each 
direction  (V1000  cubic  meter).  It  is  equal  to  1000  times  the 
volume  of  water  weighing  a  gram,  or,  in  the  English  system, 
to  a  little  more  than  a  quart. 

The  subdivisions  of  each  of  these  three  units  (meter,  gram, 
and  liter)  are  indicated  by  the  following  Latin  prefixes:  milli, 
Yiooo;  centi,  Y100;  deci,  Y10;  the  higher  denominations  by 
the  Greek  prefixes:  deka,  10;  hekto,  100;  kilo,  1000;  myria, 
10,000.  It  is  thus  seen  that  a  gram  is  the  weight  of  a  cubic 
centimeter  of  water,  and  that  1000  cubic  centimeters,  or  a 
liter,  weigh  a  kilogram.  Metric  abbreviations  are  derived  from 
the  first  letters  of  each  name:  e.g.,  c.c.,  for  cubic  centimeter; 
mg.,  milligram,  etc. 

The  metric  terms  used  in  medicine  and  pharmacy  are  the 
liter,  cubic  centimeter,  gram,  milligram,  and  micromillimeter, 
the  latter  being  a  microscopic  denomination  equal  to  1/100o 
millimeter,  or  Vioooooo  rneter;  it  is  expressed  by  the  sign  or 
letter  /*.  The  student  should  learn  the  doses  of  drugs  accord- 
ing to  the  metric  system,  bearing  in  mind  that  a  teaspoonful 
or  fluidrarn  of  liquid  medicines  is  practically  the  same  as  4 
c.c.  The  following  prescription  illustrates  the  advantages  of 
the  metric  system  in  prescription-writing.  The  numbers  rep- 
resent either  grams  or  cubic  centimeters,  according  as  the  sub- 
stance is  liquid  or  solid.  The  perpendicular  line  stands  for  the 
decimal  point,  separating  whole  numbers  from  fractions: — 

Ii  Quininae  sulphatis  2)400 

Cafieinee  citratis  1|200 

Aeetanilidi 1|800 

Fiat  pulvis;  divide  in  capsulas  nurnero  xij. 

Signa :    One  every  three  hours. 

Impenetrability.  —  No  two  bodies  can  occupy  the  same 
space  at  the  same  time.  There  are  many  apparent  exceptions 
to  this  axiom.  Sugar  disappears  without  increase  in  volume 
of  the  water.  The  air  seems  to  offer  no  hindrance  to  the 
presence  of  other  material  objects. 

Experiment. — Place  a  piece  of  lighted  candle  on  a  wide  cork  float- 
ing on  water  in  a  wide  vessel.  Over  the  cork  and  candle  press  down  a 
tall  bell-jar.  They  will  be  seen  below  the  outside  surface  of  the  liquid. 

Divisibility. — The  limits  to  which  matter  may  be  divided 
are  almost  beyond  comprehension.  Take  any  solid  substance 
and  crumble  it  in  a  mortar  or  dissolve  it  in  a  liquid;  yet  we 
know  that  the  farthest  possible  division  has  not  been  reached. 
Under  a  high  power  of  the  microscope  the  fine  grains  of  the 


4  MEDICAL  PHYSICS. 

powder  appear  large  and  rough  and  obviously  capable  of  fur- 
ther division.  Regarding  matter  in  solution,  a  grain  of  strych- 
nin renders  distinctly  bitter  a  whole  barrel  of  water.  How 
infinitely  minute  must  be  the  imponderable  particles  continu- 
ally given  off  from  a  grain  of  musk,  which  will  scent  for  years 
a  closed  apartment! 

Yet  it  is  believed,  on  good  mathematic  grounds,  that 
divisibility  has  its  bounds,  and  this  leads  us  to  the  molecular 
theory  of  the  constitution  of  matter.  Scientists  hold  that 
every  substance  is  composed  of  infinitely  minute  separate  par- 
ticles, or  molecules,  separated  by  interspaces  that  are  compara- 
tively much  larger  (according  to  Maxwell,  about  1/2  millionth 
inch  in  ordinary  air).  The  molecules  are  in  constant  motion 
(8,000,000,000  collisions  per  second  in  air),  striking  against 
each  other  and  so  producing  the  varied  forms  of  molecular 
energy  known  as  heat,  light,  magnetism,  and  electricity. 

According  to  the  relative  proximity  of  the  molecules  to 
each  other,  generally  speaking,  we  have  three  principal  states 
of  matter:  solid,  liquid,  and  gaseous, — to  which,  perhaps,  a 
fourth,  or  extragaseous — including  the  luminiferous  ether  and 
the  so-called  radiant  matter  of  artificial  vacua — may  be  added. 
These  states  are  interchangeable  under  varying  conditions  of 
temperature  and  external  pressure.  By  the  aid  of  heat  ice  is 
converted  into  water,  and  this  into  vapor.  Air  itself  has  been 
frozen  under  great  pressure  into  a  gray  powder.  The  con- 
version of  a  gas  into  a  liquid  or  a  solid  is  brought  about  either 
by  reduction  of  heat  or  by  pressure  or  both. 

Regarding  the  actual  size  of  a  molecule,  the  human  mind 
fails  to  grasp  its  nearly  infinite  minuteness.  Lord  Kelvin  esti- 
mates that  they  range  from  Vioooooooo  to  V100ooooo  cm-  in  diam- 
eter. There  are  millions  of  molecules  in  the  head  of  a  pin. 
A  crude  comparison  is  that  the  volume  of  a  drop  of  water  is 
to  that  of  each  molecule  of  which  it  is  composed  as  the  size 
of  the  earth  is  to  that  of  an  apple. 

Minute  as  are  molecules,  they  are  known  to  consist  of  even 
smaller  solid  bits  of  matter  called  atoms,  which  exist,  as  a  rule, 
only  in  combination,  forming  molecules.  When  the  constituent 
atoms  are  alike,  the  molecules,  and — of  course — the  substance 
which  they  compose,  are  termed  simple;  a  compound  molecule 
or  substance  is  composed  of  unlike  atoms. 

Attraction. — The  grand  law  of  gravitation,-  discovered  by 
Newton,  is  to  the  effect  that  every  portion  of  matter  in  the 
universe  attracts  every  other  portion  with  a  force  which  varies 
directly  as  the  mass  or  quantity  of  matter  in  the  bodies,  and 
inversely  as  the  square  of  the  distance.  The  term  gravity  is 


GENERAL  PROPERTIES  OF  MATTER.  5 

applied  to  the  attractive  force  which  the  earth  has  for  bodies 
on  or  near  its  surface. 

In  addition  to  this  molar  form  of  attraction  active  at 
sensible  distances,  the  molecules  of  each  substance  are  held 
together  by  molecular  attraction,  and  the  atoms  by  chemism, 
or  chemic  affinity,  which  is  similar  to,  if  not  identic  with, 
magnetism.  Molecular  attraction  is  of  two  general  kinds:  co- 
hesion, or  that  between  like  molecules;  and  adhesion,  or  that 
between  unlike  molecules.  The  continuity  of  a  drop  of  water 
is  an  example  of  cohesion;  water  wetting  the  finger  is  an 
illustration  of  adhesion.  When  cohesion  is  stronger  than  ad- 


Fig.  1.— Analytic  Balance. 


hesion,  a  liquid  substance  in  contact  with  a  solid  takes  and 
retains  the  globular  form. 

In  order  for  a  solution  of  a  solid  in  a  liquid  to  be  made, 
the  attraction  of  the  fluid  for  the  solid  must  be  greater  than 
that  of  the  molecules  of  the  latter  for  each  other.  When  the 
solution  is  saturated  (contains  all  it  can  of  the  dissolved  sub- 
stance), cohesion  is  just  equal  to  adhesion.  Heat,  the  repellent 
force,  is  the  great  antagonist  of  cohesion,  whereas  it  may  aid 
adhesion,  as  in  the  case  of  most  solutions.  In  solids  cohesion 
prevails  over  the  repellent  force;  in  liquids  the  two  forces  are 
about  equal,  and  the  molecules  move  around  each  other  freely; 


6  MEDICAL  PHYSICS. 

in  gases  the  repellent  force  predominates,  so  that  the  tendency 
of  a  gas  is  always  toward  greater  expansion. 

Weight  is  the  measure  of  gravity.  When  we  say  an  object 
weighs  a  pound  we  mean  that  the  earth,  as  a  whole,  draws  it 
to  an  extent  balanced  by  this  certain  weight.  The  greater  the 
mass  of  the  object  and  the  nearer  it  is  to  the  surface  of  the 
earth,  the  greater  the  attraction  and  also  the  weight.  At  the 
center  of  the  globe  a  body  would  weigh  nothing  at  all,  since 
the  attraction  of  the  encompassing  world-matter  is  equal  in 
all  directions.  A  fluidounce  of  water  weighs  457  grains.  To 
find  the  weight  of  a  given  volume  of  water  divide  by  0.96 
(avoirdupois)  or  by  1.05  (Troy  ounces). 

Specific  gravity  is  the  relative  weight  of  a  substance  as 
compared,  under  similar  circumstances  of  temperature  and 
pressure,  with  an  equal  volume  of  another  substance  taken  as 
a  standard.  Water  is  the  standard  for  both  solids  and  liquids; 
air  or  hydrogen  for  gases.  In  the  latter  instance  we  speak  of 
the  comparative  weight  as  density  rather  than  specific  gravity. 

Porosity. — The  existence  of  inconceivably  minute,  though 
relatively  large,  spaces  between  the  molecules  has  already  been 
noticed.  It  is  into  these  pores  that  in  case  of  a  solution  the 
particles  of  the  dissolved  substance  enter.  The  extent  of  these 
interspaces  is  increased  by  molecular  motion  (heat);  hence  hot 
liquids,  as  a  rule,  can  dissolve  more  of  a  given  substance  than 
cold  ones.  The  hardest  and  densest  metals  can  be  made,  under 
hydraulic  pressure,  to  show  the  presence  of  pores. 

Experiment. — Mix  50  c.c.  each  of  water  and  alcohol.  Take  the 
reading  again  in  ten  minutes,  and  note  how  much  it  falls  short  of  100 
c.c. 

Compressibility. — This  property  obviously  depends  on  the 
preceding  one,  and,  as  we  might  expect  from  the  relative  dis- 
tances between  the  component  molecules,  gases  are  more  com- 
pressible than  solids,  and  these  usually  more  so  than  liquids. 
That  most  liquids  are  less  capable  of  compression  than  most 
solids  is  due  largely  to  the  absence  in  fluids  of  sensible  pores 
or  interspaces.  The  compressibility  of  solids  is  illustrated  by 
the  stamping  of  coins  with  dies. 

Elasticity. — By  this  term  is  meant  the  tendency  of  a  body 
to  return  to  its  original  shape  after  being  compressed,  stretched, 
bent,  or  twisted,  from  which  we  have  the  four  kinds,  namely: 
elasticity  of  compression,  of  tension  or  traction,  of  flexure,  and 
of  torsion.  The  first  form  is  a  general  property  of  matter, 
though  varying  greatly  in  different  substances.  Gases  are  the 
most  elastic  form  of  matter;  liquids  come  next  in  order;  solids 
are  very  variable. 


GENERAL  PROPERTIES  OF  MATTER.  7 

Inertia. — There  is  always  a  cause  for  every  effect,  and  the 
property  of  inertia  signifies  that  nothing  material  can  of  itself 
change  its  position  or  condition.  Without  the  influence  of 
external  agents  everything  in  the  world  would  remain  the  same, 
inert  and  unvaried  for  all  time.  The  active  agents  of  natural, 
as  opposed  to  artificial,  changes  are,  first  of  all,  the  bacteria, 
those  teeming  micro-organisms  which  keep  going  the  circle  of 
life  on  the  planet  by  breaking  down  dead  animal  and  vegetable 
matter  into  more  simple  and  available  forms  for  living  things. 
Most  of  these  germs  are  innocuous,  but  some  give  rise  to  deadly 
chemic  products,  which  are,  in  turn,  responsible  for  infectious 
diseases.. 

Mobility. — All  matter  is  in  a  state  of  constant  motion; 
rest  is  only  a  relative  term.  We  may  distinguish  between 
mechanic  (visible  or  sensible)  change  of  place  and  invisible 
motion,  molecular  and  atomic — the  former  giving  rise  to  the 
physic  forces  of  heat,  light,  magnetism,  and  electricity;  the 
latter  to  the  manifold  manifestations  of  chemic  energy. 

Velocity  is  the  rate  of  motion  in  any  given  time.  Mo- 
mentum, or  quantity  of  motion,  is  the  product  of  velocity  and 
the  mass.  Force  is  that  which  causes,  alters,  or  arrests  motion. 
Energy  is  the  capacity  for  doing  work;  it  depends  on  the  union 
of  motion  and  mass.  Potential  energy  refers  to  position  or 
condition,  as  of  the  water  in  a  mill-dam  above  the  wheel;  or 
of  water-vapor,  which  in  condensing  gives  out  the  same  amount 
of  heat  required  for  evaporation.  The  potential  energy  of  a 
pound  of  coal  (11,000,000  foot-pounds)  is  equivalent  to  a  hard 
day's  work  by  a  strong  man.  Actual,  or  kinetic,  energy  is  that 
of  matter  in  motion.  Plants  generate  potential  energy,  which 
animals  render  kinetic. 

Work  is  energy  applied  to  overcome  resistance.  The  unit 
of  work,  according  to  the  English  system,  is  the  foot-pound: 
that  is,  the  amount  of  force  required  to  raise  one  pound  one 
foot  in  height;  the  corresponding  metric  unit  is  the  kilogram- 
meter.  A  horse-power  is  equivalent  to  33,000  foot-pounds  per 
minute.  Machines  gain  in  force,  but  lose  in  space. 

The  grandest  law  in  Nature  is  that  of  the  conservation 
and  correlation  of  forces:  nothing  is  wasted,  nothing  lost.  The 
ra}-s  of  the  sun  have  produced  coal,  the  coal  serves  as  fuel  to 
the  steam-engine,  the  engine  runs  the  electric  dynamo,  and 
the  latter  gives  back  the  heat  and  light  first  furnished  by  the 
sun. 


MEDICAL  PHYSICS. 


SPECIAL  PROPERTIES  OF  MATTER. 

The  special  properties  of  particular  substances  are  modi- 
fications of  the  general  attributes  of  matter.  The  three  states 
of  matter — solid,  liquid,  and  gaseous — are  dependent  upon 
the  balance  between  cohesion  and  heat:  in  other  words,  on 
the  distance  between  the  molecules.  Every  gas  and  liquid  can 
be  converted  into  the  liquid  or  solid  state  by  two  methods, 
namely:  by  cold  and  by  application  of  pressure,  singly  or  com- 
bined. Nearly  all  solids  likewise  can  be  melted  into  liquids 
and  then  vaporized.  A  few  solids — sulphur,  for  example — pass 
directly  into  the  gaseous  form  on  heating  sufficiently. 

SOLIDS. 

The  peculiar  properties  of  solids  worthy  of  mention  are 
hardness,  brittleness,  tenacity,  malleability,  ductility,  elasticity, 
flexibility,  viscosity,  and  crystallizability.  All  of  these  are 
simply  modifications  of  the  essential  property  of  cohesion. 

By  the  term  hardness  is  meant  resistance  to  scratching 
or  mechanic  erosion.  We  say  that  iron  is  hard,  lead  soft.  The 
degree  of  hardness  bears  no  relation  to  density;  lead  is  half 
again  as  heavy,  or  dense,  as  iron.  We  judge  of  the  relative 
hardness  of  any  substance  by  comparing  it  with  others  taken 
as  standards.  Mineralogists  use  a  convenient  table  of  ten 
minerals,  each  of  which  represents  a  certain  degree  of  hard- 
ness corresponding  with  a  certain  number.  The  scale  is  as 
follows: — 

1.  Talc.  6.  Feldspar. 

2.  Rock-salt.  7.  Quartz. 

3.  Calcite.  8.  Topaz. 

4.  Fluor-spar.  9.  Corundum. 

5.  Apatite.  10.  Diamond. 

The  diamond  is  the  hardest-known  substance.  It  is  used 
in  miners'  drills  and  for  cutting  glass;  the  cheaper  glass- 
cutters  are  made  of  steel.  Hard  bodies  are  much  used  as 
polishing-powders,  among  which  may  be  mentioned  emery, 
pumice,  tripoli,  and  diamond-dust.  Blacksmiths  and  workers 
in  iron  and  steel  harden  tools  and  implements  by  dipping  them 
while  heated  into  cold  water.  This  process,  called  tempering, 
usually  renders  the  metal  more  brittle.  The  best  quality  of 
glass  is  allowed  to  cool  slowly,  thereby  becoming  tougher  and 
stronger;  the  process  is  known  as  annealing. 

Brittleness  is  a  lack  of  cohesive  power,  shown  by  the  body 
breaking  when  subjected  to  moderate  strain  or  to  a  fall  or 


SPECIAL  PROPERTIES  OF  MATTER.  9 

blow.  All  brittle  substances  are  hard;  but  the  converse  is  not 
true.  The  well-known  brittle  quality  of  glass  has  become  a 
proverb  the  world  over. 

Experiment. — With  a  three-cornered  file  make  a  slight  cut  in  a 
glass  tube.  Place  a  thumb  on  either  side  of  the  cut,  on  the  opposite 
surface  of  the  glass.  With  the  remaining  fingers  make  pressure  toward 
the  thumbs.  A  neat  fracture  takes  place  readily. 

When  a  body  is  once  broken,  it  is  usually  impossible  to 
press  the  fragments  close  enough  together  for  cohesion  to  act. 
Glass  and  china  can  be  mended  only  by  the  use  of  a  different 
adhesive  material  termed  cement,  which  forms,  as  it  were,  a 
connecting  link  between  the  broken  pieces.  In  the  case  of 
wrought  iron,  however,  a  break  can  be  remedied  by  the  opera- 
tion of  welding,  by  which  the  molecules  of  the  separate  frag- 
ments are  made  to  flow  around  each  other  in  the  molten  state, 
aided  by  the  use  of  the  hammer.  Freshly  cut  lead  can  be  made 
to  cohere  again  on  strong  pressure. 

Experiment. — Take  two  glass  slides  and  place  between  them  a  few 
drops  of  water,  pressing  out  the  latter,  and  with  it  the  atmospheric 
air.  Considerable  force  will  be  required  to  pull  the  pieces  apart.  What 
two  things  are  concerned  in  the  resistance  to  the  pulling  efforts? 

Tenacity  is  that  property  of  matter  by  virtue  of  which  it 
resists  a  pulling  force.  This  property  varies  greatly  in  dif- 
ferent substances,  and  even  in  the  same  body.  A  piece  of  wood, 
for  instance,  is  more  tenacious  in  the  direction  of  the  grain 
than  across  it.  Closely  related  to  tenacity  are  the  properties 
of  elasticity,  ductility,  and  malleability. 

Elasticity  of  compression  is  a  general  property  of  matter. 
Elasticity  of  flexure  or  bending,  extension  or  stretching,  and 
torsion  or  twisting  is  restricted  to  solids.  It  is  evident  that 
in  an  elastic  body  the  molecules  return  nearly  or  quite  to  the 
relative  positions  they  occupied  before  being  acted  upon  by  the 
outside  force  or  stress. 

Malleable  bodies  are  such  as  can  be  hammered  or  rolled 
into  sheets.  Gold  and  copper  are  the  most  noteworthy  of 
the  metals  in  this  respect.  A  piece  of  the  former  metal  can 
be  beaten  into  a  film  Vsooooo  °f  an  incn  in  thickness,  and  to 
650,000  times  the  original  area. 

A  ductile  substance  is  one  that  can  be  drawn  out  into 
threads  or  wires.  Platinum  can  be  spun  into  a  web  finer  than 
that  of  the  spider.  Gold,  iron,  and  copper  are  also  remarkably 
ductile.  Certain  substances — as  sugar,  waxes,  and  glass — are 
ductile  when  heated  sufficiently,  and  dresses  even  have  been 
woven  out  of  glass.  Owing  to  increase  of  density,  the  strength 


10  MEDICAL  PHYSICS. 

or  tenacity  of  a  body  is  increased  when  it  has  been  drawn  into 
wire  or  rolled  or  hammered. 

A  flexible  body  is  one  which  will  bend  without  breaking. 
It  is  usually  also  more  or  less  elastic.  In  the  case  of  a  flexed 
body  the  molecules  on  the  inner  side  must  be  crowded  closer 
together,  while  on  the  outer  aspect  they  are  drawn  farther 
apart.  Metallic  rods  and  wires,  particularly  copper,  are,  as  a 
rule,  quite  flexible.  Certain  brittle  materials  are  readily  bent 
on  heating. 

Experiment. — Hold  a  piece  of  soft  glass  tubing  in  the  flame.  In 
a  few  seconds  the  glass  can  be  bent,  heated  portion  inward,  to  any 
required  angle. 

Viscosity  is  a  property  exhibited  by  some  brittle  substances, 
on  account  of  which  they  yield  and  bend  under  continued  stress. 
If  we  fasten  a  piece  of  sealing  wax  horizontally  by  one  end,  and 
to  the  other  attach  a  weight,  in  course  of  time  the  wax  will  be 
seen  to  be  bent  downward.  Ice  is  viscous,  as  shown  by  glaciers 
conforming  to  the  shape  of  the  valleys  through  which  they 
slowly  move. 

Crystalline  bodies  are  such  as  have  a  more  or  less  regular 
shape.  Most  natural  inorganic  substances  are  crystalline;  for 
example,  common  salt,  alum,  and  sulphate  of  copper.  Those 
substances  which  are  not  crystalline  are  termed  amorphous: 
that  is,  without  form. 

LIQUIDS. 

A  useful  and  remarkable  property  manifested  by  liquids  is 
that  of  capillary  attraction  and  repulsion. 

Experiment. — Hold  a  fine  glass  tube  in  a  beaker  of  water,  and 
another  in  a  beaker  containing  mercury.  The  water  rises  in  the  capil- 
lary tube,  because  the  adhesion  between  the  two  is  greater  than  the 
cohesive  force  of  the  water.  The  mercury  is  apparently  repelled  by  the 
glass,  since  the  cohesion  of  the  metallic  liquid  is  greater  than  its  attrac- 
tion for  the  glass. 

The  most  marked  examples  of  these  phenomena  are  seen 
in  the  smallest  tubes,  as  a  greater  relative  surface  is  thus  pro- 
vided for  the  exercise  of  attraction  or  apparent  repulsion. 
Capillary  action  is  of  immense  importance  in  Nature  and  in 
every-day  life.  In  this  way  the  sap  rises  in  plants  and  the  oil 
in  the  lamp,  the  blotting-paper  takes  up  ink,  the  towel  dries 
our  hands,  and  the  filter-paper  separates  liquids  from  undis- 
solved  solids. 

By  the  diffusion  of  liquids  is  meant  their  natural  unaided 
physic  admixture  when  their  surfaces  are  brought  into  contact. 
This  process  will  take  place,  though  more  slowly,  when  the 


SPECIAL  PROPERTIES  OF  MATTER. 


11 


lighter  fluid  is  placed  on  top  the  heavier,  as  alcohol  on  water. 
Some  liquids  will  not  mix  with  each  other  directly  at  all. 

Experiment. — Shake  a  little  water  in  a  test-tube  with  an  equal 
quantity  of  oil  of  turpentine,  and  notice  how  quickly  they  separate. 
Which  goes  to  the  top? 

The  diffusion,  or  passage,  of  two  liquids  into  each  other 
through  parchment-paper  or  an  animal  membrane  is  called 
osmosis.  Generally  speaking,  the  lighter  of  two  liquids  trav- 
erses a  porous  septum  more  rapidly  than  the  heavier  one;  its 
flow  is  termed  endosmose;  that  of  the  heavier  liquid,  exosmose. 
Crystalline  substances  have  usually  smaller  molecules  than 
amorphous  ones;  hence  they  pass  more  quickly  through  a 
porous  partition.  Bodies  capable  of  ready  osmosis  are  there- 
fore termed  crystalloids;  those  otherwise  constituted  are  called 


Fig.  2. — Capillary  Attraction  and  Repulsion. 

colloids,  which  means,  literally,  glue-like.  (See  also  under 
"Osmosis.") 

The  operation  of  separating  colloids  from  crystalloids  has 
been  termed  dialysis.  By  this  process  any  crystalline  poison, 
such  as  arsenic  or  strychnin,  can  be  easily  separated  from  the 
colloid  food-contents  of  the  stomach,  in  a  case  of  suspected 
poisoning.  Dialysis  is  also  of  use  in  the  preparation  of  dialyzed 
iron  and  some  other  drugs.  (See  also  under  "Osmosis.") 

Pressure  of  Liquids. — The  perfect  fluidity  of  water  and 
most  other  liquids  accounts  for  the  well-attested  fact  that  at 
any  given  point  in  a  liquid  the  pressure  is  the  same  in  all 
directions:  up,  down,  or  horizontally.  This  pressure  is  due  to 
gravity, — that  is,  to  the  weight  of  the  superincumbent  liquid, — 
and,  hence,  of  course,  increases  with  the  depth. 

Experiment. — To  show  that  water  presses  upward  as  well  as  down- 
ward: Attach  a  string  to  the  center  of  a  metal  disk  large  enough  to 
cover  the  bottom  of  a  glass  cylinder;  a  small  lamp-chimney  will  answer. 
Draw  the  string  through  the  tube,  holding  it  taut,  and  press  the  cylin- 


12  MEDICAL  PHYSICS. 

der  down  into  a  vessel  of  water.  At  the  depth  of  a  few  inches  one  may 
let  go  the  string,  and  the  upward  pressure  of  the  liquid  will  keep  the 
disk  from  sinking. 

Experiment. — To  prove  that  at  the  same  point  the  pressure  is 
equal  horizontally  and  perpendicularly:  Take  two  long  glass  tubes,  and 
bend  one  end  of  each  to  form  a  U,  the  open  end  of  this  facing  upward 
in  one,  outward  in  the  other,  both  openings  being  at  the  same  level. 
Pour  a  fluidram  ot  mercury  into  each  tube  and  immerse  the  U-ends  in 
a  deep  glass  vessel  of  water.  The  quicksilver  will  rise  in  both  tubes  to 
the  same  height. 

The  free  molecular  movements  and  equal  transmission  of 
pressure  in  liquids  cause  their  surface  to  be  always  level  when 
at  rest,  since  in  this  condition  only  is  equilibrium  possible; 
or,  as  expressed  in  the  old  saying:  "Water  seeks  the  lowest 
level."  Masons,  carpenters,  and  surveyors  make  use  of  a  spirit- 
level  for  determining  horizontal  lines  and  planes.  This  instru- 
ment consists  of  a  slightly  curved  tubular  glass  receptacle  set 
for  convenience  in  a  block  of  hard  wood,  and  nearly  filled  with 
alcohol.  A  small  space  is  thus  left  for  an  air-bubble,  which 
rises  to  the  center  of  the  glass  when  the  instrument  is  hori- 
zontal. 

On  account  of  the  equal  distribution  of  pressure  in  all 
directions,  a  small  quantity  of  liquid  may  apparently  counter- 
balance a  much  larger  amount,  as  in  the  familiar  example  of 
the  tea  in  the  nozzle  and  the  body  of  the  tea-pot.  The  same 
principle  is  illustrated  in  the  hydraulic  press,  used  for  exerting 
great  pressure  or  for  lifting  great  weights.  This  apparatus 
consists  essentially  of  a  large  cylinder  perforated  by  a  narrow 
conduit,  each  fitted  with  a  piston.  When  the  water  is  passed 
through  the  small  tube  into  the  larger  space  it  exerts  on  the 
sides  of  the  latter  a  distending  force  as  many  times  greater  as 
the  difference  between  the  cross-section  of  the  pipe  and  the 
inner  area  of  the  cylinder.  Yet,  in  reality,  the  total  amount 
of  energy  has  not  been  increased,  since  the  smaller  piston 
descends  a  correspondingly  greater  distance  than  the  larger  one 
rises. 

The  same  principle  of  hydrostatic  equilibrium  is  exempli- 
fied by  artesian  wells.  The  fountain-character  of  these  wells 
is  due  to  the  pressure  of  water  at  a  higher  level  upon  that 
inclosed  in  a  hollow  between  impervious  layers  of  clay,  and 
which  is  tapped  by  boring.  "Water  cannot  rise  higher  than 
its  source,"  and,  owing  to  friction  of  soil  and  air,  the  heights 
of  these  wonderful  fountains  are  probably  much  below  the  level 
of  their  origin. 

Pressure  on  Immersed  Bodies. — The  difference  between  the 
pressures  on  the  upper  and  lower  surfaces  of  a  body  immersed 


SPECIAL  PROPERTIES  OF  MATTER. 


13 


in  a  liquid  is  evidently  equal  to  the  weight  of  the  liquid  dis- 
placed, since  such  pressure  increases  in  exact  proportion  with 
the  depth.  This  difference  represents  likewise  the  apparent  loss 
of  weight  of  a  solid  substance  when  immersed  in  a  liquid,  or  the 
so-called  buoyant  force  of  liquids. 

Experiment. — Weigh  a  piece  of  iron  in  air  and  then  suspend  in 
water.  How  much  does  it  appear  to  lose  in  weight?  Now  weigh  the 
water  and  vessel  before  and  after  immersion  of  iron.  How  much  do  they 
appear  to  gain  in  weight '( 

Since  the  apparent  loss  of  weight  of  the  solid  equals  the 
weight  of  liquid  displaced,  it  is  easy  to  find  by  simple  com- 
parison their  relative  weights,  which  in  the  case  of  water  is 


Fig.  3.— Hydrostatic  Balance. 

called  specific  gravity.  To  find  the  specific  gravity  of  the  iron 
in  the  above  experiment,  we  need,  therefore,  only  to  divide  its 
weight  in  air  by  its  apparent  loss  of  weight  when  weighed  in 
water. 

If  we  use  metric  measures  the  solid  need  be  weighed  only 
in  air.  It  is  then  placed  in  a  carefully  measured  quantity  of 
water  in  a  metric  graduate.  The  number  of  c.c.  the  water  rises 
is  equivalent  to  the  mass  of  the  solid,  and  a  comparison  of  this 
rise  with  the  weight  in  grams  of  the  solid  shows  at  once  the 
specific  gravity.  This  applies  to  fine  powders  as  well  as  con- 
crete masses. 

Experiment. — Find  the  sp.  gr.  of  a  silver  dollar  and  of  powdered 
sulphur. 


14  MEDICAL  PHYSICS. 

The  volume  of  an  irregular  body  is  readily  estimated  by 
weighing  it  in  air  and  then  immersing  it  by  a  string  in  water 
and  weighing  again.  The  apparent  loss  of  weight  in  grams 
equals  the  volume  of  the  body  in  c.c. 

If  a  solid  is  soluble  in  water,  we  may  ascertain  its  relative 
weight  in  some  other  liquid  not  a  solvent,  multiplying  the 
result  by  the  known  sp.  gr.  of  the  liquid  employed. 

Experiment. — Find  sp.  gr.  of  cane-sugar,  using  turpentine  as  a 
medium. 

With  solids  lighter  than  water  a  lead  sinker  is  attached. 
The  calculation  is  made  as  for  heavy  substances,  bearing  in 
mind,  however,  that  the  light  object  weighed  in  water  appears 
to  lose  its  own  weight  and  more.  For  example,  a  piece  of  lead 


Fig.  4.—  Picnometer. 


5. — Hydrometer. 


weighing  10  gm.  in  water  has  attached  to  it  a  piece  of  cork 
weighing  2  gm.  in  air.  The  two  now  weighed  in  water  weigh 
4  gm.  The  apparent  loss  of  weight  is  12  —  4  =  8  gm.  Divid- 
ing 2  gm.,  the  weight  of  the  cork,  by  8  gm.,  its  apparent  loss 
of  weight  in  water,  we  find  its  sp.  gr.  to  be  0.25. 

The  picnometer,  or  specific-gravity  flask,  is  a  thin,  round 
bottle  with  a  perforated  glass  cork  and  a  counterpoise.  The 
flask  is  usually  made  to  contain  exactly  1000  grains  of  distilled 
water  at  60°  F.  If  when  filled  with  chloroform  the  weight  is 
1500  grains,  we  know  that  the  sp.  gr.  of  the  latter  must  be  1.5. 

Experiment. — Find  the  sp.  gr.  of  alcohol  with  the  picnometer. 

The  sp.  gr.  of  liquids, 'however,  is  usually  taken  with  the 
hydrometer,  which  is  an  instrument  consisting  of  a  graduated 


SPECIAL  PROPERTIES  OF  MATTER.  1  .-> 

stem  above,  a  hollow  cylinder  midway,  and  a  bulb  below  con- 
taining quicksilver  or  shot.  The  instrument  depends  on  the 
theorem  of  Archimedes,  that  a  body  immersed  in  a  liquid  dis- 
places its  own  volume  and  loses  weight  equal  to  the  weight  of 
the  liquid  displaced,  and  that  the  immersed  body  sinks  until 
it  has  displaced  a  volume  of  the  liquid  equal  to  its  own  weight. 
The  stem  of  the  instrument  is  marked  so  that  the  surface 
reading  is  1.000  for  pure  water  (at  15°  C.  unless  otherwise 
stated),  and  so  on  up  or  down  with  solutions  of  known  sp.  gr. 
The  Baume  scale  instruments  are  of  two  kinds:  for  liquids 
lighter  than,  and  for  those  heavier  than,  water.  The  reading 


Fig.  6.— Westphal  Specific  Gravity  Balance. 

is  generally  taken  at  the  top  of  the  meniscus,  or  little  ring  of 
liquid  clinging  upward  around  the'  stem  of  the  instrument. 
Modifications  of  the  hydrometer  for  special  fluids  are  the  uri- 
nometer,  the  lactometer  (for  milk),  salimeters,  saccharimeters, 
vinometers,  and  alcoholimeters. 

The  sp.  gr.  of  liquids  can  also  be  determined  by  weighing 
a  solid  body  of  known  weight  in  them.  It  is  evident  that  the 
apparent  loss  of  weight  of  the  solid  is  greater  in  the  heavier 
liquid  than  in  the  lighter  one,  and  their  relative  densities  are 
obtained  by  a  simple  ratio.  For  example,  a  piece  of  iron  loses, 
let  us  say,  2  gm.  by  weight  in  water,  1.45  gm.  in  other:  the 
sp.  gr.  of  ether  is  the  ratio  of  1.45  to  2,  or  0.725.  This  prin- 


16  MEDICAL  PHYSICS. 

ciple  is  utilized  in  the  convenient  Westphal  balance,  consisting 
of  a  notched  beam  attached  at  one  end  to  a  perpendicular  sup- 
port, and  having  at  the  other  end  a  hook  supporting  a  rider,  a 
thermometer,  and  a  glass  plummet.  When  these  are  immersed 
in  distilled  water  at  15°  C.  the  arm  of  the  instrument  is  exactly 
horizontal.  In  liquids  other  than  water  the  sp.  gr.  is  read  at 
a  glance  from  the  numbered  notches  on  which  riders  of  various 
sizes  are  placed  in  order  to  bring  the  arm  to  the  horizontal. 

GASES. 

The  constitution  of  gases  is  in  many  respects  more  simple 
than  the  structure  of  solids  or  liquids.  The  Italian  physicist 
Avogadro  and  the  French  electrician  Ampere  discovered  and 
^  demonstrated  about  the  same  time  the  following  law:  Equal 

volumes  of  all  bodies  in  the  gaseous  state  and  at  the  same  tem- 
perature contain  the  same  number  of  molecules.  The  neces- 
sary corollaries  of  this  principle  are,  first,  all  gaseous  molecules 
occupy  the  same  space;  second,  the  relative  weights  of  any 
two  gases  are  to  each  other  as  the  weights  of  their  molecules. 

The  volume  of  a  confined  gas  is  inversely  proportional  to 
the  pressure  brought  to  bear  upon  it.  This  statement  is  called 
Mariotte's  law.  One  atmosphere  (760  mm.  of  mercury)  is  taken 
as  the  standard  of  pressure. 

Charles's  law  is  to  the  effect  that  the  volume  of  any  sub- 
stance in  the  gaseous  state  varies  directly  as  the  absolute  tem- 
perature. It  has  been  found  that  a  lowering  of  temperature 
from  1°  to  0°  C.  reduces  the  volume  of  a  gas  by  1/273,  or  vice 
versa.  Hence  at  a  point  273°  below  zero  all  molecular  motion 
must  cease  and  the  molecules  be  in  contact  with  each  other. 
•  This  is  called  the  absolute  zero,  from  which  absolute  tempera- 
ture is  reckoned.  In  calculating  the  volume  of  a  gas  zero 
centigrade  is  considered  the  standard. 

The  tendency  to  expansion  exhibited  by  all  gases  is  due 
to  the  repulsion  between  the  molecules.  All  gases  expand  at  a 
uniform  rate  for  equal  increments  of  heat:  11/300o  increase  in 
volume  for  every  degree  above  0°.  The  constant  tendency  of 
an  inclosed  gas  to  escape  from  its  container  is  called  its  ten- 
sion, or  elastic  force.  The  tension  and  the  density  of  an 
inclosed  gas  vary  inversely  as  its  volume. 

The  diffusion,  or  mixing,  of  one  gas  with  another  depends 
upon  tension,  and  the  rapidity  of  diffusion  varies  inversely  as 
the  square  root  of  the  density  of  each  gas.  Wet  membranes 
allow  the  diffusion  of  soluble  gases  more  readily  than  do  dry 
ones,  as  exemplified  by  the  diffusion  of  carbon  dioxid  from  the 


SPECIAL  PROPERTIES  OF  MATTER. 


17 


Mood  into  the  lungs.  Damp  walls  are  unhealthful,  because 
they  prevent  normal  diffusion  of  air. 

We  live  at  the  bottom  of  an  aerial  ocean  at  least  ten  times 
as  deep  as  the  watery  oceans  which  envelop  the  land.  The  air, 
like  all  gases,  is  a  perfect  fluid,  and  hence  subject  to  all  the 
laws  of  pressure  and  equilibrium  of  liquids.  The  pressure  of 
the  atmosphere  at  sea-level  is  about  15  pounds  to  the  square 
inch,  or  the  equivalent  of  the  weight  of  a  column  of  mercury 
760  mm.,  or  30  inches,  in  height.  As  we  ascend  from  the  level 
of  the  ocean  the  atmospheric  pressure  gradually  lessens,  so  that 
at  Denver,  for  instance,  it  will  sustain  a  column  of  mercury  but 
25  inches  high,  and  at  an  altitude  of  3  1/8  miles  only  15  inches. 

The  barometer  is   an  instrument   for  measuring  atmos- 


Fig.  7. — Mercurial  Barometer. 


pheric  pressure.  It  was  invented  by  Torricelli  in  1643,  and 
consisted  of  a  simple  glass  tube  closed  at  one  end.  The  tube 
is  filled  with  mercury  and  then  inverted  in  a  basin  of  the  same, 
when  the  metal  sinks  until  its  own  weight  equals  the  pressure 
of  the  atmosphere  on  an  area  the  same  as  that  of  a  cross-section 
of  the  tube.  This  primitive  arrangement,  properly  graduated, 
is  still  in  use  under  the  name  of  the  cistern  barometer.  The 
ordinary  mercurial  barometer  consists  of  a  long  arm  joined  to 
a  short  one,  the  former  being  closed  above,  the  latter  open. 
The  space  above  the  quicksilver  in  the  long  tube  is  termed  a 
Torricellian  vacuum.  The  difference  in  level  of  the  height  of 
the  liquid  in  each  arm  represents  the  atmospheric  pressure. 
This  varies  with  altitude  and  with  the  temperature  and  humid- 
ity of  the  air.  At  sea-level  in  fair  weather  it  is  760  mm.,  or  a 


18  MEDICAL  PHYSICS. 

little  more  than  30  inches.  Fair  weather  is  manifested  by  a 
high  barometer;  a  sudden  fall  foretells  a  storm. 

It  is  readily  seen  that  the  barometer  can  be  used  for  as- 
certaining the  heights  of  mountains  or  the  distance  above  sea- 
level  at  any  elevation.  For  this  purpose  the  convenient  aneroid 
barometer  is  usually  employed.  It  consists  of  an  hermetically- 
sealed,,  flat,  circular  box  of  corrugated  sheet-iron  exhausted  of 
air.  The  sides  of  it  are  pressed  in  more  or  less  with  each  varia- 
tion of  atmospheric  pressure,  indicated  by  a  needle  on  the  dial- 
face  connected  with  the  interior  arrangement  of  levers. 

On  atmospheric  pressure  depends  the  action  of  pumps, 
siphons,  bulb-syringes,  pipets,  and  medicine-droppers.  The 
pressure  of  the  air  (at  sea-level)  will  sustain  a  column  of  water 
34  feet  in  height,  and  this  is  evidently  the  greatest  distance 
that  water  can  be  raised  by  means  of  a  suction-pump.  The 
propelling  force  of  a  liquid  in  a  siphon  is  equal  to  the  difference 
between  atmospheric  pressure  and  the  weight  of  the  liquid  in 
the  short  arm,  minus  the  same  difference  in  the  case  of  the 
longer  arm. 

Light,  bulky  bodies  float  in  air  or  are  borne  up  to  a  certain 
degree  by  the  buoyant  force,  depending  on  inequality  of  press- 
ure at  different  depths.  For  this  reason,  a  pound  of  feathers 
as  weighed  in  air  weighs  more  than  a  pound  in  a  vacuum.  A 
balloon  may  rise  to  a  great  height,  because  of  its  great  volume 
of  gas  lighter  than  air.  The  highest  ascent  was  that  of 
Glaisher  in  1861,  who  attained  an  elevation  of  over  36,000 
feet. 

Gases  are  absorbed  by  liquids  and  solids,  the  absorption 
in  the  latter  instance  being  termed  occlusion.  The  amount 
absorbed  varies  greatly  for  different  gases,  increasing  with  in- 
crease of  pressure  and  decreasing  with  a  rise  in  temperature. 
In  most  instances  the  absorption  is  accompanied  by  feeble 
chemic  action.  Charcoal  is  a  striking  example  of  an  absorbent 
solid,  taking  up  90  times  its  own  volume  of  ammonia-gas. 
Water  has  great  avidity  also  for  ammonia,  1  volume  at  15°  C. 
dissolving  783  volumes  of  the  gas. 

Experiment. — Fill  a  cylinder  with  ammonia  by  driving  this  gas  out 
of  ammonia-water  with  the  aid  of  heat  and  collecting  by  upward  dis- 
placement. Place  the  cylinder,  mouth  downward,  in  a  vessel  of  water, 
and  agitate  slightly.  Why  does  the  water  rise  in  the  cylinder? 

The  sp.  gr.  of  a  gas  can  be  ascertained  by  filling  a  thin 
glass  globe  with  the  gas  and  comparing  its  weight  with  the 
weight  of  the  same  volume  of  air,  or,  more  frequently,  hy- 
drogen (density).  Allowance  must  be  made  mathematically  for 
differences  in  temperature  and  atmospheric  pressure. 


HEAT.  19 

Three  or  more  volumes  of  combining  gases  condense  into 
two  volumes. 

Cardiac  failure  on  going  to  high  altitudes  is  due  to  sudden 
decrease  in  extracardiac  without  any  corresponding  decrease  in 
intracardiac  pressure,  which  remains  about  760  mm.,  as  shown 
by  manometer.  This  difference  leads  to  acute  cardiac  dilation. 
In  estimating  the  pressure  on  the  heart  6  mm.  should  be  de- 
ducted for  the  tension  required  to  overcome  the  elastic  force 
of  the  air-cells. 

HEAT. 

Heat  is  molecular  motion.  Cold  is  a  relative  term,  sig- 
nifying merely  a  low  degree  of  heat.  The  principal  source  of 
heat,  both  directly  and  indirectly,  is  the  sun,  although  the 
earth  receives  only  about  a  two-billionth  part  of  the  solar 
radiant  energy.  The  sun  clothes  our  planet  with  vegetable  life, 
which  is  used  largely  for  fuel,  either  in  the  primary  condition 
of  wood  or  transformed  into  coal,  gas,  and  oil.  A  layer  of  ice 
thirty-five  yards  thick  could  be  melted  annually  by  the  direct 
heat  of  the  sun. 

The  fixed  stars  furnish  us  with  no  small  amount  of  heat. 
The  interior  of  the  earth  is  thought  to  be  in  a  molten  state 
(with  a  hard,  central  core),  as  evidenced  by  volcanoes,  geysers, 
and  hot  springs.  The  temperature  increases  as  we  descend  into 
the  earth:  about  1°  F.  for  every  50  to  100  feet.  There  is  no 
seasonal  change  below  30  feet.  Atmospheric  temperature 
diminishes  about  1°  C.  for  each  rise  of  160  meters. 

Mechanic  friction,  percussion,  and  pressure  are  common 
causes  of  heat.  We  rub  our  hands  or  a  patient's  body  to  make 
it  warm.  Some  savage  people  still  start  their  fires  by  revolving 
the  sharpened  end  of  a  stick  of  wood  in  another  dry  piece.  It 
is  only  about  seventy-five  years  since  the  flint  and  tinder  were 
supplanted  by  matches.  A  beautiful  natural  illustration  of  the 
development  of  heat  by  friction  is  seen  in  the  "shooting  stars," 
or  meteorites,  celestial  bodies  of  low  density,  which  become  so 
intensely  heated  on  passing  through  our  atmosphere  as  to  burst 
into  consuming  flame. 

Artificial  heat  is  produced  generally  by  chemic  action, 
especially  by  the  oxidation  (oxygen-combination)  of  substances 
rich  in  the  elements  carbon  and  hydrogen,  as  are  all  ordinary 
fuels.  Animal  heat  originates  in  chemic  action,  namely:  the 
oxidation  of  carbon  and  hydrogen  in  the  tissues. 

Experiment. — Add  some  sulphuric  acid  to  water,  and  note  heat 
produced.  Is  this  a  physic  or  chemic  change? 


20  MEDICAL  PHYSICS. 

Whatever  may  be  the  special  source  of  heat  in  any  par- 
ticular instance,  we  are  convinced  that  there  has  been  merely 
a  transformation  of  some  other  kind  of  energy  into  this. 

Transmission  of  Heat. — This  occurs  in  three  ways:  by  con- 
duction, by  convection,  and  by  radiation.  Conduction  is  trans- 
mission by  continuity  from  one  portion  of  a  body  to  another, 
as  when  an  iron  poker  grows  gradually  hot  from  the  end  which 
is  in  the  fire  to  the  opposite  extremity.  Different  substances 
vary  greatly  in  the  facility  with  which  they  carry  heat.  Metals, 
as  a  rule,  are  good  conductors.  Wood  is  a  poor  conductor; 
hence  is  used  for  the  handles  of  iron  culinary  vessels.  Air  is 
also  a  poor  conductor.  Woolen  clothing  is  warmer  in  winter 
and  cooler  in  summer  than  other  fabrics,  because  of  its  loose 
texture.  The  air  it  contains  in  the  pores  prevents  the  inward 
passage  of  heat  to  the  body  in  summer  and  the  outward  passage 
of  body-warmth  in  winter.  Poor  conductors  are  employed  to  a 
large  extent  for  packing  purposes  to  prevent  freezing  or  thaw- 
ing. Examples  of  such  uses  are  sawdust  for  ice,  straw  for 
cellars,  and  asbestos  for  water-pipes.  Gutta-percha  and  zinc- 
oxid  cements  are  poor  conductors,  and  are  commonly  employed 
to  protect  the  pulp  before  filling  a  cavity  with  a  dental  amalgam 
alloy. 

Experiment. — To  prove  that  water  is  a  poor  conductor  of  heat: 
Pack  powdered  ice  or  snow  firmly  at  the  bottom  of  a  test-tube,  and 
boil  the  upper  portion  of  the  water  above.  The  ice  or  snow  does  not 
melt. 

In  convection  heat  is  diffused  by  currents  of  liquids  or 
gases,  the  warmer  portion  of  the  fluid  rising,  while  colder 
streams,  being  heavier,  descend  to  fill  the  vacated  space.  Ven- 
tilation, the  renewal  of  air  in  mines  and  buildings,  is  accom- 
plished by  convection,  a  double  current  of  warm  and  cool  air 
being  established  by  reason  of  the  difference  of  temperature 
inside  and  outside  the  inclosed  space. 

Experiment. — To  show  convection  in  fluids:  Boil  some  colored 
anilin  in  water  in  a  beaker. 

The  transmission  of  heat  by  spheric  wave-motion  through 
the  ether  or  the  air  is  called  radiation.  This  is  the  manner 
in  which  the  radiant  energy  emitted  by  the  sun  comes  to  us. 
Non-luminous  bodies  also  radiate  heat  with  varying  rapidity, 
a  stone  faster  than  leaves  or  grass,  and  these  more  quickly 
than  water.  Radiant  rays  are  either  reflected,  absorbed,  or 
transmitted.  Polished  surfaces  are  good  reflectors  of  heat  as 
well  as  of  light.  Dark,  rough  surfaces  greedily  absorb  radiant 
energy;  hence  become  quickly  heated.  Well-blackened  stoves 


HEAT.  21 

radiate  more  heat.  Transparent  and  diaphanous  substances 
generally  transmit  heat  with  little  loss,  and  are  therefore  hardly 
affected  themselves  as  to  temperature.  They  are  diathermous 
to  solar  heat,  but  more  or  less  athermous  to  the  slower  waves 
radiated  back  from  the  earth:  the  principle  of  green-houses. 
The  top  of  a  mountain,,  though  nearer  the  sun,  is  much  colder 
than  the  base,  because  of  the  lesser  amount  of  soil  to  absorb 
the  heat,  and  because  the  air  itself  retains  scarcely  any  of  the 
radiant  energy  which  passes  through  it.  The  difference  in 
temperature  between  direct  sunshine  and  shadow  is  accounted 
for  by  the  presence  or  absence  of  solar  radiant  heat,  just  as 
pulling  down  the  window-curtains  cools  a  room. 

Effects  of  Heat.  —  The  manifold  effects  of  heat  are  all 
manifestations  simply  of  the  enhanced  motion  of  the  mole- 
cules. It  is  this  quickening  of  molecular  movements  which 
constitutes  heat  the  repellent  force,  the  antagonist  of  cohesion. 
Heat  expands  and  cold  contracts.  The  principal  exception  to 
this  rule  is  water,  which  expands  one-tenth  on  changing  to  ice 
with  a  force  of  30  pounds  to  the  square  inch.  Sulphur,  cast- 
iron,  and  type-metal  expand  on  cooling.  Gases  expand  and 
contract  equally  and  uniformly;  liquids  and  solids  unequally. 
The  action  of  applied  heat  is  a  double  one:  raising  the  tem- 
perature and  changing  the  state  of  the  substance  acted  on. 

Temperature,  or  sensible  heat,  is  the  direct  manifestation 
of  heat  to  our  senses.  We  say  that  a  body  is  warm  or  cold, 
meaning  that  it  gives  off  heat  to  our  hands  or  takes  it  from 
them.  If  a  cup  of  boiling  water  is  let  stand  on  the  table,  it 
radiates  heat  until  it  is  of  the  same  temperature  as  the  sur- 
rounding air. 

For  the  exact  measurement  of  temperature  (intensity,  not 
quantity,  of  heat)  we  use  instruments  called  thermometers, 
first  invented  in  1609.  These  consist  essentially  of  a  closed 
glass  tube  containing  mercury,  with  a  reservoir-bulb  at  the 
bottom  and  a  scale  of  degrees.  Heat  expands  the  mercury, 
causing  it  to  rise  in  the  tube;  cold  has  the  opposite  effect. 

There  are  three  kinds  of  thermometers  in  use,  the  Celsius, 
or  centigrade;  the  Fahrenheit,  and  the  Reaumur.  The  first 
named  is  the  one  employed  by  scientists  the  world  over;  the 
second  is  the  ordinary  household  instrument;  the  last  is  now 
used  only  in  Russia,  Sweden,  and  Denmark.  The  centigrade 
scale  is  to  be  understood  as  being  used  in  this  book  whenever 
it  is  not  stated  to  the  contrary. 

Each  thermometer-tube  is  first  filled  with  mercury,  which 
is  boiled,  and  then  the  glass  is  sealed.  To  mark  the  scale  two 
standard  points  are  furnished  by  Nature,  that  of  boiling  water, 


22  MEDICAL  PHYSICS. 

or  steam  (the  boiling-point),  and  that  of  freezing  water  or  melt- 
ing ice  (the  freezing-point),  or  equal  weights  of  snow  and 
ammonium  chlorid.  The  bulb  of  the  instrument  is  placed  in 
melting  snow  and  then  in  steam,  and  marks  are  made  corre- 
sponding to  the  summit  of  the  mercurial  column  in  each  case. 
All  that  is  left  to  be  done  is  to  divide  the  intermediate  space 
into  degrees  of  equal  width:  100  for  the  centigrade,  80  for 
the  Reaumur,  and  180  for  the  Fahrenheit  instrument.  The 
part  of  the  tube  above  boiling-point  and  that  below  freezing- 
point  are  divided  in  the  same  way  into  degrees.  In  numbering 


<C          JBL         Jff. 

Fig.  8.— Comparison  of  Thermometer  Scales. 

degrees  the  f.p.  in  both  Reaumur  and  the  centigrade  scales 
is  marked  0°;  b.p.,  100°  C.  in  centigrade,  80°  R.  in  Reaumur. 
The  b.p.  of  the  Fahrenheit  scale  is  numbered  212°  F.;  f,p.  32° 
F.,  the  zero  in  this  scale  being  thus  32°  below  the  f.p.  of  water, 
representing — the  inventor  mistakenly  thought — the  coldest 
attainable  temperature.  Water  boils  at  211°  F.  in  a  rough 
iron  vessel,  and  several  degrees  higher  in  a  very  smooth  vessel. 
It  freezes  below  zero  when  very  still,  and  when  at  or  below  the 
freezing-point  may  congeal  en  masse  when  its  container  is 
slightly  shaken. 

Since  100°  C.  equals  180°  Fv  it  is  evident  that  to  change 


HEAT.  23 

centigrade  degrees  into  Fahrenheit  degrees  we  must  multiply 
by  18%oo>  or  %;  and  to  convert  P.  degrees  into  C.  degrees  we 
multiply  by  5/9.  One  other  thing  needs  to  be  taken  into  con- 
sideration, namely:  that  the  P.  zero  is  32°  below  f.p.  There- 
fore, to  convert  a  centigrade  reading  into  the  P.  scale  we  should 
multiply  by  9/5  and  add  32°;  whereas  the  reverse  operation 
requires  that  we  first  subtract  32°  and  then  multiply  by  f>/9. 
Since  Hg  freezes  about  —  40°  and  boils  at  357  V4°,  some  other 
substances  must  be  used  for  the  extremes  beyond  these  points. 
Alcohol  (colored)  thermometers  are  employed  for  very  low 
temperatures  (alcohol  freezes  at  — 130°),,  and  bars  of  platinum 
measure  by  expansion  very  high  temperatures;  no  two  solids 
have  the  same  rate  of  expansion.  Pyrometers  are  instruments 
for  measuring  temperatures  above  the  b.p.  of  mercury.  They 
depend  on  electric  changes  induced  by  heat  or  on  expansion 
of  gases. 

The  figures  given  above  refer  to  the  b.p.  of  pure  water 
at  sea-level.  A  rise  in  altitude,  by  decreasing  the  amount  of 
atmospheric  pressure,  lowers  the  b.p.  at  the  rate  of  1°  P.  for 
every  533  feet  of  ascent  above  the  sea-level.  The  altitude 
of  any  place  may  be  easily  ascertained  by  applying  this  fact. 
When  water  is  heated  under  more  than  ordinary  atmospheric 
pressure,  the  b.p.  is  raised  and  the  digestant  action  of  the  fluid 
much  increased. 

Experiment. — The  culinary  paradox:  Fill  a  glass  flask  one-third 
full  with  water  and  heat  till  boiling  thoroughly,  then  cork  tightly  and 
invert  the  flask.  Ebullition  quickly  ceases.  Why?  It  begins  again  and 
continues  if  cold  water  is  poured  over  the  flask.  Why? 

Experiment. — By  means  of  a  flask  and  a  thermometer  take  the 
b.p.  of  water  and  estimate  altitude. 

The  effect  of  pressure  upon  the  f.p.  (or  melting-point)  is 
obviously  to  lower  it  (make  the  change  more  difficult)  in  sub- 
stances— water,  for  instance — which  expand  on  solidifying. 
Examples  are  a  snowball  and  the  track  of  ice  made  by  a  sled 
in  the  snow;  the  f.p.  rises  when  the  pressure  is  removed.  On 
the  other  hand,  pressure  aids  (raises  the  f.p.)  the  solidification 
of  liquids  which  contract  on  passing  into  the  solid  state.  The 
presence  of  solids  in  solution  renders  freezing  and  vaporization 
both  more  difficult,  and  hence  raises  the  b.p.  and  lowers  the 
f.p.  Examples  of  this  fact  are  the  use  of  salt  on  icy  car-tracks 
and  the  making  of  ice-cream.  Water  saturated  with  common 
salt  has  a  b.p.  of  109°;  with  K2C03?  135°;  with  CaCl,,  179°. 

Raoult's  law  is  to  the  effect  that  the  lowering  of  the  f.p. 
of  an  aqueous  solution  below  the  f.p.  of  pure  water  is  propor- 
tionate to  the  number  of  molecules  dissolved  in  the  unit  of 


24  MEDICAL  PHYSICS. 

volume  of  the  liquid,  whatever  be  the  nature  and  weight  of  the 
molecules. 

The  b.p.  of  other  liquids  is  not  the  same  as  that  of  water. 
Pure  anesthetic  ether  will  boil  in  the  hand  in  a  test-tube. 
Mercury  changes  into  a  gas  at  357°.  Ammonia  volatilizes  from 
its  liquid  form  at  about  the  same  temperature  at  which  mer- 
cury freezes,  namely:  — 40°. 

Experiment. — Find  b.p.  of  alcohol. 

The  f.p.,  or  solidifying-point,  of  most  liquids  is  identic 
with  their  melting-points  when  in  a  solid  state.  Melting  ice 
and  freezing  water,  for  example,  have  precisely  the  same  tem- 
perature. The  most  infusible  metal  is  iridium,  which  melts  at 
1950°;  and  next  to  this  comes  platinum. 

Medical  thermometers  are  made  self-registering  by  a  con- 
striction of  the  lower  part  of  the  tube,  which  permits  the 
passage  of  the  liquid  upward  in  small  drops  under  the  greater 
force  of  heat,  but  causes  a  break  when  contraction  begins, 
gravity  not  being  sufficient  to  force  the  mercury  downward. 
The  same  principle  is  utilized  in  the  maximum  meteorologic 
thermometers.  The  minimum  meteorologic  thermometers  con- 
tain alcohol  and  an  index  of  black  glass,  which  is  sucked  down 
by  capillary  attraction  between  it  and  the  alcohol,  and  remains 
at  the  lowest  level  reached  by  the  column  of  fluid  in  the  tube. 
These  two  varieties  are  also  called  recording  thermometers. 

Thermometers  that  have  been  used  for  a  long  time  are 
likely  to  give  slightly  higher  readings,  owing  to  the  crushing 
in  of  the  glass  at  the  bulb  by  external  atmospheric  pressure, 
the  space  not  occupied  by  mercury  having  been  made  a  vacuum. 
Thermometers  should  be  seasoned  for  at  least  a  year  before 
marking,  in  order  to  let  the  glass  reach  its  ultimate  stage  of 
contraction  after  the  heating  it  has  undergone. 

Specific  Heat.  —  Not  all  substances  become  heated  with 
equal  rapidity.  The  water  in  the  tea-kettle  is  cool  after  the 
iron  is  heated,  and  remains  warm  after  the  vessel  and  stove 
have  cooled.  Except  the  gas  hydrogen,  water  has  the  greatest 
capacity  for  heat  of  any  substance;  that  is,  it  requires  more 
heat  to  warm  it  and  gives  out  more  heat  in  cooling  than  any- 
thing else  except  hydrogen.  For  this  reason  a  coast  climate 
is  more  equable  than  inland  weather;  in  the  night  the  heat 
of  the  slowly  cooling  ocean  flows  over  to  the  land,  while  by 
day  the  water  draws  off  warmth  from  the  rapidly  heated  sand 
and  soil.  The  ratio  of  the  capacity  for  heat  of  any  substance 
as  compared  with  an  equal  weight  of  water  is  termed  its 
specific  heat.  Mercury,  for  instance,  becomes  heated  30°  while 


HEAT.  25 

the  same  weight  of  water  rises  only  1°  in  temperature.  The 
specific  heat  of  mercury  is  therefore  0.0333.  That  of  iron  is 
0.1138;  of  air,  0.2375;  of  ice,  0.5040.  Every  substance  has  its 
own  specific  heat,  which  increases  with  temperature:  more  in 
liquids,  except  water. 

Experiment. — Put  on  each  side  of  a  double  porcelain  vessel  equal 
weights  of  water  and  mercury,  and  heat  as  equally  as  possible.  Com- 
pute the  specific  heat  of  the  liquid  metal. 

Atomic  heat  is  a  constant:  about  6.4.  The  specific  heat 
of  any  substance  equals  its  atomic  weight  divided  by  this  con- 
stant. The  various  effects  of  applied  heat  depend  upon  ex- 
pansion, and  include  such  phenomena  as  liquefaction,  evapora- 
tion, distillation,  sublimation,  and  solution. 

Liquefaction. — This  signifies  the  change  from  a  solid  to 
a  liquid  state.  It  takes  place  for  each  substance  at  a  particular 
melting-point,  which  remains  the  same  until  all  the  body  has 
been  liquefied,  when  the  temperature  again  rises.  As  already 
stated,  the  melting-point  is,  for  the  same  substance,  ordinarily 
the  same  as  its  f.p.  Animal  and  vegetable  substances  are  gen- 
erally decomposed  without  liquefying  on  heating  sufficiently. 
Certain  alloys  melt  at  a  lower  temperature  than  boiling  water, 
and  are  used  extensively  in  automatic  fire-extinguishers. 

Evaporation. — The  slow  and  natural  vaporization  of  water 
that  takes  place  continuously  from  the  surface  of  the  globe  is 
.termed  evaporation.  The  rapidity  of  evaporation  varies  directly 
with  temperature,  atmospheric  dryness,  and  extent  of  surfaces 
of  water  and  air  exposed  to  each  other;  it  varies  inversely 
with  atmospheric  pressure.  Chemists  employ  wide  and  shallow 
vacuum  vessels  for  evaporating  purposes.  We  have  all  experi- 
enced the  oppressive  discomfort  of  damp,  sultry  days  when  the 
air  contained  already  as  much  water-vapor  as  it  could,  and 
hence  the  cooling  process  of  evaporation  from  the  skin  was 
greatly  impeded.  It  is  easy  to  see  that  the  sensible  tempera- 
ture need  not  correspond  at  all  with  that  shown  by  the  ther- 
mometer. 

A  rise  of  10°  C.  nearly  doubles  the  capacity  of  the  air  for 
moisture  (5.4  gm.  to  a  cubic  meter  at  0°),  but  evaporation  goes 
on,  though  much  more  slowly,  even  below  the  f.p.  In  changing 
from  the  liquid  to  the  gaseous  state  great  expansion  takes  place; 
a  cubic  inch  of  water  becomes  a  cubic  foot  of  steam.  The 
student  should  remember  that  water  when  evaporated  is  taken 
up,  not  as  a  liquid,  but  as  a  vapor,  which  mixes  with  the  air 
just  as  other  gases  do.  The  only  distinction  between  a  vapor 
and  other  gases  is  that  the  former  condenses  readily  into  the 


26  MEDICAL  PHYSICS. 

liquid  form,  while  the  latter  do  not.  By  critic  temperature  is 
meant  the  degree  above  which  a  gas  cannot  be  reduced  by 
pressure  to  the  liquid  form.  The  critic  temperature  of  air  is 
—  194°;  of  water-vapor,  400°. 

The  capacity  of  air  for  heat  depends  chiefly  upon  the  pro- 
portion of  water-vapor  it  contains.  This  fact  makes  a  differ- 
ence of  about  30°  F.  between  sun  and  shade  in  the  dry  Rocky 
Mountain  regions. 

When  air  contains  so  much  water-vapor  that  the  least 
lowering  of  temperature  would  precipitate  the  latter  in  the 
liquid  or  solid  form  as  dew,  fog,  mist,  clouds,  rain,  hail,  or 
snow,  the  air  is  said  to  be  saturated,  and  the  temperature  at 
the  time  is  called  the  dew-point.  The  air  seems  dry  if  its  tem- 
perature is  much  above  the  dew-point;  moist,  if  the  tempera- 
ture and  the  dew-point  are  nearly  or  quite  the  same.  The  air 
of  a  furnace-heated  room  contains  more  total  water-vapor  than 
does  the  cold  air  outside;  but  relative  to  the  dew-point  and  to 
our  sensations  the  outer  atmosphere  is  humid,  the  inner  dry. 
The  air  of  a  room  when  excessively  dry  can  be  made  more  moist 
by  keeping  a  pan  of  water  on  the  stove  or  furnace.  The  rela- 
tion of  the  temperature  to  the  dew-point  at  a  given  time  is 
usually  expressed  in  the  meteorologic  reports  as  percentage  of 
relative  humidity. 

The  hygrometer  is  a  simple  apparatus  for  estimating  the 
relative  humidity  of  the  atmosphere.  It  consists  of  a  glass 
tube  filled  with  water  and  fitted  with  a  wick,  which  covers  and 
keeps  constantly  wet  the  bulb  of  one  of  two  thermometers 
placed  side  by  side.  Evaporation  of  moisture  from  the  wick 
cools  the  mercury  underneath  and  lowers  the  temperature  of 
this  thermometer.  The  dryer  the  atmosphere,  the  greater  the 
difference  in  readings  of  the  two  thermometers.  Sensible  tem- 
perature is  that  of  the  wet-bulb  thermometer,  and  is  usually 
about  10°  F.  less  than  the  dry  bulb  in  Colorado;  much  less 
difference  is  found  near  the  sea-coast. 

Distillation.  —  Artificial  vaporization  is  used  principally 
for  the  purification  or  separation  of  water  and  other  liquids. 
It  is  conducted  at  the  b.p.  of  the  liquid  distilled  in  an  apparatus 
called  a  still.  This  consists  essentially  of  a  retort,  or  flask,  in 
which  the  substance  is  boiled,  and  a  condenser.  The  latter  is 
a  long  glass  or  spiral  copper  tube  connected  with  the  retort  and 
surrounded  by  a  vessel  or  a  larger  tube  in  which  cold  water  is 
kept  running.  The  cold  water  condenses  the  passing  vapor 
into  drops,  which  run  out  at  the  lower  end  of  the  condenser. 

Experiment. — Distil  colored  water,  using  a  flask  connected  with  a 
Liebig  condenser,  and  catch  the  colorless  product  in  a  beaker. 


HEAT.  27 

Ebullition  in  a  boiling  liquid  is  due  to  the  heat  suddenly 
expanding  the  gases  contained  in  a  liquid.  It  may  be  prevented 
to  some  extent  by  placing  in  the  retort  some  porous  substance, 
like  pumice-stone,  to  absorb  the  gases. 

By  fractional  distillation  is  meant  the  separation  by  vola- 
tilization of  one  liquid  from  another,  or  of  several  from  each 
other.  It  depends  on  different  liquids  having  different  b.p/s. 
To  distil  alcohol,  for  example,  from  a  mixture  of  alcohol  and 
water,  such  as  wine,  the  liquid  is  heated  only  to  the  b.p.  of 


Fig.  9.— Apparatus  for  Distillation. 


alcohol,  which  vaporizes,  leaving  most  of  the  water  behind. 
Destructive  distillation  is  a  term  applied  to  the  vaporization, 
with  chemic  decomposition,  of  solid  substances,  such  as  wood. 
Sublimation. — The  direct  transformation  of  a  substance 
from  the  solid  into  the  gaseous  state  is  called  sublimation, 
lodin,  sulphur,  camphor,  and  corrosive  sublimate  are  examples 
of  sublime  substances.  The  process  of  sublimation  is  used 
mainly  for  purifying  purposes,  and  is  sometimes  repeated  (re- 
sublimation). 


28  MEDICAL  PHYSICS. 

Experiment. — Heat  iodin,  and  catch  vapor  in  paper  cone. 

Experiment. — Heat  impure  ammonium  chlorid  in  the  bottom  of  a 
large  test-tube;  watch  it  sublime  and  collect  in  pure,  white,  crystal- 
line masses  in  the  upper  part  of  the  tube. 

Solution. — Heat  aids  the  solution  of  solids  in  liquids,  but 
interferes  with  the  absorption  of  gases.  The  process  of  solu- 
tion is  not  thoroughly  understood,  but  probably  consists  in 
a  change  similar  to  fusion,  followed  by  mechanic  admixture. 
When  a  solid  substance  dissolves  in  a  liquid  without  the  ap- 
plication of  heat,  the  necessary  heat  is  taken  from  the  liquid 
itself,  cooling  it  accordingly.  If,  however,  a  chemic  reaction 
takes  place,  the  liquid  becomes  warmer.  A  physic  solution, 
therefore,  is  marked  by  a  lowering  of  temperature;  a  chemic, 
by  a  rise  in  temperature.  The  solution  of  a  gas  in  a  liquid 
raises  its  temperature. 

Experiment. — Make  a  saturated  aqueous  solution  of  potassium 
iodid.  Is  it  cold  or  hot? 

Experiment. — Dissolve  a  little  quicklime  in  water.  Is  it  hot  or 
cold t 

A  liquid  which  dissolves  solid  substances  is  said  to  be  a 
solvent  for  them.  Water  is  the  best  solvent  for  a  great  pro- 
portion of  drugs  and  medicines;  alcohol  comes  next  in  dis- 
solving power;  then  ether,  chloroform,  turpentine,  and  fixed 
oils.  Percentage  solutions  are  usually  by  weight.  A  fluidounce 
of  water  weighs  457  grains;  the  same  quantity  of  alcohol,  374 
grains. 

The  solubility  of  any  substance  in  a  solvent  is  always  the 
same  at  the  same  temperature,  which  for  convenience  is  stated 
at  15°  C.  in  the  tables  of  solubility.  Different  substances  vary 
greatly  in  their  solvents  and  their  solubility.  Some  are  so 
soluble  in  water  that  they  absorb  moisture  from  the  air  and 
become  liquid.  Such  bodies  are  called  deliquescent  or  hygro- 
scopic. The  opposite  property  of  becoming  dry  when  exposed 
to  the  air  is  termed  efflorescence. 

When  a  solvent  can  take  up  no  more  of  a  substance  it  is 
said  to  be  saturated;  if  it  can  take  up  a  little  more,  the  solution 
is  concentrated;  if  it  can  take  up  a  good  deal  more,  the  solu- 
tion is  dilute.  A  saturated  solution  of  one  substance  does  not 
prevent  the  taking  up  of  any  other  solid  and  may  even  aid  such 
an  occurrence.  The  total  amount  of  two  or  more  substances 
capable  of  being  dissolved  is  always  greater  than  that  of  any 
one  alone. 

Experiment. — To  a  solution  of  mercuric  chlorid  add  excess  of 
potassium  iodid.  The  red  mercuric  iodid  is  first  precipitated,  then  re- 


HEAT.  29 

dissolved.    Potassium  iodid  is  also  employed  to  aid  the  solution  of  iodin 
in  water.    A  little  cane-sugar  makes  borax  more  soluble  in  water. 

A  practical  knowledge  of  the  solubility  of  common  drugs  is 
necessary  to  physicians  in  prescribing  liquid  mixtures.  Water 
is  the  solvent  to  be  chosen  for  most  mineral  and  alkaloidal 
salts,  gums,  sugars,  albumins,  gelatins,  and  solid  acids.  Alco- 
hol is  the  solvent  for  resins,  gum-resins  (dilute  alcohol),  bal- 
sams, volatile  oils,  and  stearoptens.  Ether  dissolves  fats  and 
fixed  oils.  Glycerin  is  a  ready  solvent  for  earthy  salts  (alum, 
borax)  and  tannin.  Fixed  oils  dissolve  sulphur  and  phosphorus. 
Carbon  disulphid  is  a  good  solvent  for  sulphur.  Chloroform 
dissolves  gutta-percha.  Turpentine  is  a  solvent  for  paints,  fats, 
fixed  oils,  and  sulphur.  Mercury  dissolves  nearly  all  metals 
except  iron. 

A  solution  of  a  non-volatile  inorganic  substance  in  water 
is  called  a  liquor;  of  a  volatile  or  gaseous,  an  aqua.  If,  instead 
of  simple  water,  the  solvent  used  is  a  concentrated  aqueous 
solution  of  cane-sugar,  we  have  a  syrup.  Infusions  are  prepara- 
tions made  by  treating  vegetable  substances  with  cold  water; 
decoctions  are  similar,  but  hot  water  is  used  instead  of  cold. 

Tinctures  are  alcoholic  solutions  of  non-volatile  (iodin 
excepted)  principles  of  drugs;  spirits  are  solutions  in  alcohol 
of  volatile  medicinal  agents;  essences  are  stronger  spirits. 

Soluble  substances  are,  as  a  rule,  more  soluble  in  hot  than 
in  cold  water  or  other  liquid.  In  case  of  a  chemic  solution, 
however,  such  as  that  of  quicklime  in  water,  the  reverse  is  true, 
as  there  are  in  cold  water  more  molecules  present  to  enter  into 
chemic  combination  than  in  the  same  volume  of  warmer  water. 
Common  salt  is  about  as  soluble  in  cold  as  in  hot  water.  So- 
dium sulphate  is  most  soluble  in  water  at  33°.  The  process  of 
solution  is  aided  also  by  pulverizing  the  substance  to  be  dis- 
solved, thus  rendering  it  more  easy  of  access  to  the  molecular 
attraction  of  the  menstruum.  Other  means  of  hastening  solu- 
tion are  shaking  the  vessel  and  trituration  of  the  solid  with 
the  liquid. 

When  fluids  mingle  together  physically  they  do  so  in  no 
definite  proportions.  Fluids  immiscible  with  water  are  held  in 
suspension  by  the  aid  of  some  viscid  excipient,  as  acacia,  soap, 
gums,  and  white  of  egg,  or  in  the  form  of  soap  with  an  alkali. 
Turpentine  emulsion,  for  example,  is  made  by  rubbing  up  1 
part,  by  weight,  of  oil  of  turpentine  with  1  of  gum  arabic, 
slowly  adding  the  same  amount  of  water  with  continual  tritura- 
lion.  Milk  is  a  natural  emulsion,  the  tiny  fat-globules  of  which 
are  held  up  and  apart  by  shells  of  casein.  Emulsions  separate 
spontaneously  on  standing  for  a  longer  or  shorter  time,  in  this 


30  MEDICAL  PHYSICS. 

way  also  differing  from  true  solutions,  which  are  broken  up 
only  by  the  formation  of  crystals. 

Divers  Effects  of  Heat. — Heat  aids  chemic  changes  by  in- 
creasing the  space  between  the  molecules,  which  are  often 
decomposed  into  smaller  ones.  Organic  molecules,  being  larger 
than  inorganic  ones,  dissociate  (are  broken  up)  at  a  lower  tem- 
perature than  the  latter,  which,  as  a  rule,  can  sustain  heating 
to  more  than  1000°  F. 

Experiment. — Heat  sugar  on  platinum.  Note  charring  character- 
istic of  organic  compounds. 

Another  interesting  effect  of  heat  is  change  of  color. 
Orange-red  antimony  sulphid  turns  black  on  drying  thoroughly. 
Mercuric  iodid  changes  from  scarlet  red  to  orange-yellow  on 
heating,  becoming  red  again  on  cooling.  Mercuric  oxid  at  a 
very  low  temperature  ( — 200°)  fades  from  scarlet  to  pale 
orange. 

Experiment. — Heat  a  little  zinc  oxid  in  a  test-tube  over  the  flame. 
It  becomes  light  yellow,  turning  white  again  on  cooling. 

Heat  generally  improves  the  malleability  and  ductility  of 
metals.  Most  metals  and  solid  compounds  become  brittle  with 
great  cold. 

Latent  Heat.  —  We  have  already  seen  that  a  solid  body 
when  heated  sufficiently  rises  in  temperature  until  its  melting- 
point  is  reached,  when  the  temperature  remains  stationary  (if 
crystalline;  still  rises  more  or  less  if  amorphous,  like  sealing 
wax)  until  liquefaction  is  complete,  and  then  rises  to  the  b.p., 
at  which  temperature  the  liquid  stays  until  it  is  entirely  vapor- 
ized. The  heat  which  is  used  up  thus  in  overcoming  cohesion 
and  changing  the  state  of  a  substance  is  called  by  the  rather 
misleading  name  of  latent  (hidden)  heat.  When  a  gas  becomes 
again  a  liquid  or  a  liquid  a  solid,  all  this  heat  is  given  out  again 
as  temperature.  Steam-heating  depends  on  this  principle,  the 
vapor,  being  condensed  in  the  pipes,  gives  off  its  latent  heat. 
We  are  familiar  with  the  usual  warm  and  sultry  feeling  pre- 
ceding a  storm,  this  feeling  being  due  to  the  giving  off  of 
latent  heat  during  condensation  of  water-vapor.  Latent,  or 
insensible,  heat  performs  a  very  important  part  in  the  muta- 
tions of  the  seasons,  moderating  sudden  changes  both  of  thaw- 
ing and  of  freezing. 

Change  of  material  form  always  implies  the  presence  of 
heat,  and  this  heat  is  abstracted  from  the  nearest  convenient 
source.  We  cool  a  room  or  a  street  by  sprinkling  water  on  the 
surface;  to  change  the  water  into  vapor  heat  is  taken  from  the 


HEAT.  31 

air.  The  sudden  expansion  of  the  confined  gas  when  a  bottle 
of  light  wine  or  beer  is  opened  reduces  the  temperature  in  the 
neck  of  the  flask  so  much  that  a  fog  appears  in  it.  Artificial 
ice  is  made  on  the  same  principle  by  the  expansion  of  liquefied 
ammonia  into  gas  in  vacuum  apparatus  arranged  in  tanks  filled 
with  water,  the  cooling  action  being  aided  by  the  use  of  brine. 
Freezing  mixtures  depend  on  the  utilization  of  heat  in  one 
or  more  of  three  ways,  namely:  by  evaporation,  by  solution, 
and  by  expansion  of  gases.  Considerable  cooling  is  also  effected 
by  radiation.  Drinking-water  in  warm  countries  is  kept  cool 
by  placing  it  in  flat  vessels  on  straw  or  in  porous  water  jugs. 

Experiment. — Spray  ether  on  the  hand,  or  dip  a  thermometer  for 
a  moment  in  this  liquid,  and  note  how  many  degrees  the  temperature 
is  lowered  by  the  time  the  instrument  is  dry. 

Experiment. — Mix  some  ammonium  nitrate  with  an  equal  volume 
of  water,  and  note  effect. 

Just  as  heat  can  be  produced  by  mechanic  energy,  so  again 
it  can  be  transformed  into  the  latter.  Stationary  and  locomo- 
tive steam-engines,  hot-air  and  gas-  engines  are  illustrations. 
All  of  these  depend  on  pressure  due  to  the  expansive  force,  or 
tension,  of  matter  in  the  form  of  gas. 

Calorimetry,  —  Calorimeters  are  instruments  designed  to 
measure  the  quantity  of  heat  in  substances.  There  are  four 
methods  of  calorimetry:  By  fusion,  volatilization,  and  warming 
water  or  cooling.  For  instance,  the  ice-calorimeter  consists  of 
a  block  of  ice  with  a  cavity  closed  by  a  cover.  The  body  to  be 
tested  is  placed  at  a  certain  temperature  in  the  cavity  and  left 
there  until  it  has  cooled  to  0°.  The  quantity  of  water  pro- 
duced by  the  melting  of  the  ice  in  the  cavity  is  then  weighed, 
and  the  relation  between  cause  and  effect  expressed  in  heat- 
units.  Again,  the  quantity  of  heat  in  a  body  can  be  readily 
measured  by  plunging  it  into  a  certain  quantity  of  water  at  a 
known  temperature  and  noting  the  number  of  degrees  the 
water  rises. 

Thermal  Units. — The  amount  of  heat  required  to  raise  the 
temperature  of  a  kg.  of  water  1°  C.  is  called  a  calorie;  to  raise 
1  pound  1°  C.,  a  thermal  unit.  One  calorie  equals  2.2  thermal 
units.  If  we  mix  a  kg.  of  water  at  80°  with  the  same  weight 
of  pounded  ice  at  0°,  the  water  will  dissolve  the  ice,  and  the 
temperature  of  the  resulting  liquid  will  be  0°  C.  Stated  briefly, 
80  calories  are  required  to  convert  ice  into  water.  In  changing 
the  water  into  vapor  537  calories  are  used  up.  In  other  words, 
it  takes  more  than  five  times  as  long  (temperature  of  flame 
stationary)  to  "boil  away"  a  given  quantity  of  water  as  to  raise 
its  temperature  from  f.p.  to  b.p. 


32  MEDICAL  PHYSICS. 

Carefully  performed  experiments  by  the  English  physicist 
Joule  have  established  the  fact  that  the  amount  of  heat  neces- 
sary to  raise  the  temperature  of  a  pound  of  water  1°  F.,  when 
transformed  into  mechanic  energy  is  equal  to  772  foot-pounds, 
or  for  1  kg.  424  kgm.  This  number,  therefore,  is  termed  the 
mechanic  equivalent  of  heat,  and  is  usually  expressed  by  the 
abbreviation  J. 

LIGHT. 

Light  is  that  form  of  radiant  energy  which  gives  rise  to 
visual  sensations.  It  is  believed  to  consist  in  vibrations  of 


Fig.  10.—  Kadiometer. 

ether,  a  continuous,  imponderable,  transparent,  structureless, 
infinitely  tenuous,  perfectly  elastic,  frictionless,  rigid,  and  in- 
compressible body  filling  all  space,  whether  apparently  vacant 
or  occupied.  This  hypothetic  ether  is  the  great  medium  of 
transfer  of  energy:  of  gravitation  as  well  as  of  molecular  and 
atomic  forces.  Indeed,  there  are  not  wanting  eminent  physi- 
cists who  hold  that  ether  is  the  only  true  matter,  and  that 
molecules  and  masses  perceptible  to  our  senses  are  but  varying 
combinations  of  ethereal  vortex  rings:  in  other  words,  of  ether 
in  motion.  Light-waves  proper  differ  from  the  accompanying 
heat-waves  in  being  shorter,  and  hence  of  greater  velocity;  the 


LIGHT.  33 

chemic,  or  actinic,  waves  of  radiant  energy  are  shorter  and 
more  rapid  than  those  of  light. 

The  radiometer  consists  of  a  hollow  glass  sphere  on  a 
stand;  the  sphere  is  nearly  a  vacuum,  containing  about  a 
millionth  of  an  atmosphere:  the  so-called  radiant  matter. 
Within  the  globe  are  four  little  vanes,  of  aluminum,  bright 
on  one  side,  dark  on  the  other,  and  suspended  on  a  platinum 
support  so  as  to  revolve  easily  when  brought  into  the  sunlight 
or  near  a  flame.  The  revolutions  are  due  to  the  difference  in 
force  with  which  the  light-waves  act  upon  the  two  sides  of  the 
vanes,  being  absorbed  most  by  the  blackened  surfaces. 

Experiment. — Show  presence  of  heat  in  the  solar  rays  by  lighting 
a  piece  of  oiled  black  paper  with  a  burning-glass.  A  fire  might  be 
started  in  this  way  even  with  a  lens  of  ice. 

Experiment. — Show  actinic  effect  of  solar  energy  on  a  piece  of 
white  filter-paper  dipped  in  a  strong  solution  of  silver  nitrate,  dried  in 
a  dark  place,  then  covered  with  a  wire  gauze  and  exposed  to  sunlight. 

Light  travels  always  in  straight  lines,  and  its  oscillations 
are  at  right  angles  to  the  plane  of  projection,  like  a  rope  shaken 
at  one  end.  A  ray  of  light  is  simply  a  line;  a  beam  is  a  col- 
lection of  rays,  whether  parallel,  convergent,  or  divergent;  a 
pencil  differs  from  a  beam  only  in  its  greater  area. 

A  luminous  body  is  one  which  emits  light.  An  illuminated 
object  is  one  on  which  light  falls.  Transparent  or  diaphanous 
substances,  like  glass,  permit  the  free  passage  of  light-rays. 
Translucent  bodies  allow  some  of  the  light  to  pass,  but  not 
enough  to  define  distinctly  objects  on  the  farther  side.  Opaque 
substances  intercept  all  the  light.  Metals  are  opaque  except  in 
very  thin  layers,  when  they  are  translucent.  A  shadow  is  the 
contour  projection  of  an  opaque  or  translucent  object  produced 
by  the  stoppage  of  light. 

The  principal  source  of  terrestrial  light  is  the  sun.  Other 
sources  of  natural  light  are  the  so-called  fixed  stars,  meteors, 
comets,  volcanoes,  and  the  lightning-flash.  Artificial  light  is 
usually  the  result  of  combustion  or  of  resistance  to  the  passage 
of  electricity. 

The  emission  of  light  from  a  heated  substance  (above 
1000°  F.)  without  chemic  action  is  termed  incandescence; 
hence  incandescent  lamps  (electric  and  Welsbach  burners). 
Calorescence  signifies  nearly  the  same  as  incandescence;  the 
heat-waves  are  converted  into  light-rays  by  concentration  upon 
platinum  or  other  metal. 

By  phosphorescence  is  meant  the  power  of  some  substances 
to  emit  light,  accompanied  with  little  or  no  heat,  under  the 
influence  of  nervous,  chemic,  thermal,  or  mechanic  stimuli. 


34  MEDICAL  PHYSICS. 

Spontaneous  phosphorescence  is  exhibited  by  fireflies  and  jelly- 
fishes  as  the  result  of  nervous  energy;  it  is  also  seen  in  a  solu- 
tion of  phosphorus,  being  due,  in  this  instance,  to  slow  oxida- 
tion; decaying  organic  substances,  especially  fish  and  the  willow 
tree,  often  shine  in  the  dark.  Two  pieces  of  loaf  sugar  rubbed 
together  in  the  dark  produce  a  phosphorescent  glow.  The 
sulphid  and  the  cyanid  of  calcium  are  phosphorescent  for  some 
hours  after  exposure  to  the  rays  of  the  sun. 

From  astronomic  calculations,  it  has  been  determined  that 
the  solar  light  travels  at  the  rate  of  186,337  miles  per  second, 
a  speed  almost  inconceivable;  yet  it  takes  10,000  years  for  a 
ray  of  light  to  cross  the  visible  universe.  In  water  light  travels 
three-fourths  as  fast  as  in  air. 

Light  is  reflected  just  as  other  forces  are,  the  angle  of 
incidence  being  equal  at  all  times  to  the  angle  of  reflection. 
The  amount  of  light  reflected  is  greatest  when  the  illuminant 
is  near  the  horizontal;  least,  when  at  the  vertic  meridian.  A 
rough  reflector  diffuses  or  disperses  the  rays  of  light  in  all 
directions,  and  so  reveals  its  own  outline;  a  smooth  surface 
reflects  the  rays  without  altering  their  relation  to  each  other, 
and  thus  furnishes  an  image  of  the  luminous  object  or  of  an 
opaque  body  placed  between  the  latter  and  the  reflector.  A 
concave  mirror  converges  parallel  rays  of  light;  a  convex 
mirror  has  the  opposite  effect.  The  student  should  study  the 
images  observed  on  the  two  sides  of  a  lamp-reflector,  and  illus- 
trate their  differences  by  diagrams. 

Images  formed  by  actual  union  of  reflected  rays  are  termed 
real;  when  this  union  is  apparent  only  and  back  of  the  mirror, 
they  are  called  virtual  images  (plane,  convex,  and  concave — 
with  point  of  light  between  principal  focus  and  mirror).  The 
point  in  the  axis  of  a  mirror  at  which  reflected  rays  meet  is 
termed  the  focus.  This  is  always  half-way  between  the  center 
of  the  mirror  and  the  center  of  curvature:  that  is,  the  center 
of  the  circle  which  would  be  produced  by  prolonging  the  curve 
of  the  mirror.  The  kaleidoscope  consists  essentially  of  three 
plane  mirrors  with  pieces  of  colored  glass  set  in  a  pasteboard 
tube. 

Befraction. — A  ray  of  light  in  passing  obliquely  from  a 
rarer  into  a  denser  medium  (as  from  air  to  water)  is  bent 
toward  the  perpendicular;  away  from  the  perpendicular  when 
traveling  in  the  opposite  direction.  It  is  for  this  reason  that 
an  oar  appears  broken  at  the  surface  of  the  water,  and  that 
stars  a  little  below  the  horizon  are  visible.  The  index  of  re- 
fraction is  the  ratio  of  the  sine  of  the  angle  of  incidence  to 
that  of  the  angle  of  refraction;  for  the  same  substances  it  is 


Ll(  JUT. 


33 


a  constant  quantity.  The  index  of  refraction  from  water  into 
air  is  three-fourths;  from  air  into  water,  four-thirds.  When 
the  angle  of  refraction  of  an  incident  ray  is  more  than  a  right 
angle  (critic  angle)  with  the  perpendicular,  the  ray  does  not 
(•merge,  hut  is  reflected;  this  phenomenon  is  called  total  re- 
flection. 

Experiment. — Look  upward  obliquely  into  a  glass  filled  with  water. 
Note  that  one  cannot  see  beyond  the  mirror-like  upper  surface. 

The  mirage  of  the  desert  furnishes  a  beautiful  example 
of  total  reflection,  the  image  of  trees  and  water  beyond  the 
horizon  being  reflected  from  denser  strata  of  air  at  some  dis- 
tance above  the  surface  of  the  earth.  In  the  same  way — that 
is,  by  difference  in  refractive  power  of  its  layers — air  itself 
becomes  visible,  as  when  heated  by  a  stove  or  the  sun.  The 
diamond  is  the  most  refractive  of  solids,  and  its  brilliancy  de- 
pends mainly  on  this  property  of  internal  reflection.  Another 


Fig.  11.— Lenses. 

example  of  total  reflection  is  the  camera  lucida  attached  to  the 
eye-piece  of  a  microscope  and  used  for  sketching  objects. 

A  prism  is  any  transparent  refractive  body  the  sides  of 
which  form  acute  angles  with  each  other.  Prisms  used  in 
chemistry  and  medicine  are  termed  lenses.  According  to  form 
there  are  six  classes  of  lenses,  namely:  convex,  concave,  plano- 
convex, plano-concave,  concavo-convex  (converging  meniscus), 
and  convexo-concave  (diverging  meniscus).  Lenses  which  are 
thicker  in  the  center  converge  rays  of  light;  those  which  are 
thinner  centrally  have  a  divergent  action.  Convex  glasses  are 
used  in  spectacles  for  far-sight;  concave  ones  for  near-sight. 
A  simple  microscope  consists  essentially  of  a  single  convex  lens. 
A  compound  microscope  has  two  convex  lenses;  one  is  the 
object-glass,  and  the  other  in  the  eye-piece  "magnifies"  the 
enlarged  image  formed  by  the  first  lens. 

A  telescope  differs  from  a  compound  microscope  in  having 
a  very  large  object-glass  in  order  to  catch  as  many  rays  of  light 
as  possible.  An  opera-glass  contains  a  convex  and  a  concave 


36  MEDICAL  PHYSICS. 

lens.  The  camera  obscura  cf  the  photographer  resembles  the 
human  eye  in  the  presence  of  a  convex  lens  in  the  front  part 
of  the  instrument.,  and  a  screen  sensitive  to  light  at  the  rear. 
The  image  is  reversed  in  both  instances.  The  stereoscope  has 
two  lenses,  each  of  which  is  plano-convex  toward  the  center  of 
the  frame,  and  double  convex  in  its  outer  part.  The  ophthal- 
moscope is  a  small,  concave  mirror  with  a  central  opening, 
behind  which  small  lenses  are  passed  until  the  examiner  can 
see  the  retina  distinctly. 

Color. — In  addition  to  their  refractive  effects,  prisms  dis- 
perse or  break  up  white  light  into  its  component  colors.  The 
prism  usually  employed  for  this  purpose  is  triangular  and  equi- 
angular. The  hues  thus  produced  are  infinite  in  variety,  but 
seven  colors  stand  out  distinctly  in  the  following  order:  Violet, 
indigo,  blue,  green,  yellow,  orange,  red,  the  red  being  least 
refracted,  the  violet  most.  This  dispersion  of  sunlight  into 
the  seven  bands  of  the  rainbow  forms  the  solar  spectrum.  The 
violet  waves  are  shortest  (Veoooo  inch)  and  most  frequent 
(739,000,000,000,000  per  second);  the  red  waves  are  longest 
r/MtM  incn)  and  slowest  (428,000,000,000,000  per  second). 
The  sensation  of  various  color  depends,  therefore,  on  the  num- 
ber of  wave-impacts  of  light  upon  the  retina  in  a  given  second 
of  time;  difference  in  brilliancy  depends  on  the  relative  force 
of  the  blows;  direct  sunlight  is  too  dazzling  for  the  human 
eye.  The  intensity  of  light,  as  measured  by  the  photometer, 
varies  inversely  as  the  square  of  the  distance  from  the  luminous 
source,  as  also  with  the  angle  of  incidence.  The  sun's  light  is 
only  one-seventh  as  intense  at  5°  above  the  horizon  as  at  the 
zenith.  The  earth  is  nearer  the  sun  in  winter  than  in  summer, 
but  the  increased  obliquity  of  the  solar  rays  much  more  than 
offsets  the  decrease  in  distance. 

White  light,  then,  is  composed  of  seven  colors.  This  fact 
may  be  proved  by  analysis  with  one  prism  and  by  synthesis  with 
another.  Two  colors  that  when  taken  together  produce  white 
are  said  to  be  complementary  to  each  other.  Examples  of  such 
are  purple  and  green,  red  and  bluish  green,  orange  and  cyan- 
blue,  yellow  and  ultramarine,  yellowish  green  and  violet.  Com- 
plementary colors  are  the  best  for  producing  contrast-effects 
in  dress  or  otherwise. 

Experiment. — Make  a  weak  solution  of  a  nickel  and  of  a  cobalt 
salt.  When  mixed  together  carefully  the  pink  and  the  green  colors 
unite  to  produce  a  colorless  fluid. 

When  we  gaze  at  a  certain  color  for  some  minutes  the  eye 
becomes  fatigued  for  this  hue,  and  if  now  we  look  at  something 


LIGHT.  37 

white  or  into  space  we  see,  not  the  first  color,  but  its  comple- 
ment. 

The  color  of  any  object  is  not  of  itself,  but  of  the  light 
that  it  acts  upon,  absorbing,  reflecting,  or  transmitting.  In 
the  dark  everything  is  black.  A  red  light  gives  a  corresponding 
tinge  to  all  objects  in  its  path.  Looking  through  green  goggles, 
even  the  snow  takes  on  the  tint  of  grass.  Black  represents  the 
absence  of  all  colors:  that  is,  total  absorption.  A  blue  object 
is  one  which  reflects  or  transmits  to  the  eye  only  the  wave- 
lengths of  this  hue.  Transparent  substances  may  have  one 
color  by  reflected  light,  another  by  transmitted  light;  one  may 
be  the  complement  of  the  other. 

Experiment. — Add  to  a  beaker  of  water  a  few  drops  each  of  a 
solution  of  eosin  and  of  hematoxylin.  The  mixture  is  green  by  reflected 
light,  purple-red  by  transmitted  light. 

Water  in  large  masses  appears  blue  or  green.  The  blue 
color  of  the  sky  is  owing  to  the  refrangibility  of  the  violet  rays 
being  greater  than  those  colors  at  the  opposite  end  of  the 
spectrum;  hence  when  the  sunlight  floods  the  atmosphere,  the 
bluish  waves  are  bent  down  to  us  most  of  all.  The  red  and 
yellow  waves  are  longer  and  stronger  than  the  blue,  and  to  this 
are  due  the  color-effects  of  sunrise  and  sunset,  when  the  solar 
light  must  traverse  a  much  greater  layer  of  air  than  when  the 
sun  is  nearer  the  zenith. 

Experiment. — Dry  some  red  mercuric  iodid  on  a  sheet  of  paper 
over  a  lamp.  It  changes  to  yellow,  the  red  color  being  restored  on 
shaking  or  rubbing.  The  variation  is  ascribed  to  changes  in  crystalline 
structure. 

Iridescence  is  the  name  applied  to  the  beautiful  play  of 
colors  seen  in  cracks  in  glass,  in  soap  bubbles,  and  in  the 
plumage  of  birds  and  the  lining  of  many  shells.  The  phe- 
nomenon is  produced  by  interference  of  secondary  waves  set  up 
by  thin  films  of  air  or  by  lines.  Newton's  rings  illustrate  color- 
effects  due  to  interference  by  pressure.  This  apparent  bending 
of  the  light-rays  about  lines  and  angles  is  known  as  diffraction. 
Diffraction-gratings  are  made  of  glass,  the  surface  of  which  is 
ruled  with  fine  lines  very  close  together.  They  give  a  well- 
marked  spectrum. 

By  fluorescence  is  meant  the  bluish  opalescence  seen  in 
kerosene  and  other  petroleum  compounds  and  in  fluor-spar. 
The  appearance  is  due  to  the  refraction  of  the  actinic  rays  in 
such  a  manner  as  to  render  them  visible. 

Actinism. — Most  chemic  substances  are  acted  upon  to  some 
degree  by  the  actinic  rays  that  accompany  solar  light.  This 
is  particularly  true  of  silver  salts,  hydrogen  peroxid,  and  of 


38  MEDICAL  PHYSICS. 

iodids  of  various  metals.  Actinic  changes  are  prevented  or 
retarded  by  keeping  susceptible  substances  in  blue  or  amber- 
colored  bottles. 

Salts  of  silver  are  decomposed  by  light,  with  deposition  of 
metallic  silver,  especially  in  the  presence  of  organic  matter; 
hence  they  stain  the  skin.  Photographers  employ  sensitized 
plates  and  papers  coated  on  one  side  with  a  film  of  collodion, 
albumin,  or  gelatin,  containing  an  emulsion  of  silver  chlorid, 
bromid,  or  iodid.  The  development  of  negatives  is  done  in  a 
dark  room  with  some  reducing  substances,  like  hydroquinon, 
and  then  a  fixing  agent,  commonly  sodium  thiosulphate,  which 
dissolves  the  unreduced  silver  salt  and  fixes  the  metal.  The 
photograph  is  obtained  from  the  negative  by  exposing  the  latter 
over  sensitized  paper  to  direct  sunlight. 

Experiment. — Illustrate  photography  by  means  of  a  leaf  pinned 
to  a  piece  of  white  filter-paper,  previously  dipped  in  a  solution  of  silver 
nitrate  and  dried  in  the  dark. 

Spheric  aberration  is  the  term  applied  to  the  confusion  of 
images  arising  from  the  difference  in  focus  between  the  rays 
which  penetrate  the  central  portion  of  a  lens  and  those  that 
are  refracted  by  its  outer  zone.  This  defect  is  best  corrected 
by  the  use  of  a  circular  ring  diaphragm,  which  shuts  off  light 
from  passing  through  the  edge  of  the  lens.  A  good  illustration 
of  such  a  mechanism  is  the  iris  of  the  eye. 

Chromatic  aberration  results  from  the  difference  in  re- 
frangibility  of  the  various  color-rays.  The  violet  come  to  a 
focus  sooner  than  the  others,  and  so  give  to  the  outer  part  of 
the  visual  field  a  disagreeable  coloration.  In  microscopes  the 
defect  is  overcome  by  combining  a  convex  lens  of  crown  glass 
with  a  concave  meniscus  of  flint  glass,  constituting  the  achro- 
matic lens,  in  which  two  of  the  three  principal  colors  are 
brought  to  a  focus.  Apochromatic  lenses  contain  also  calcium 
fluorid,  and  bring  all  three  colors  to  the  same  focus. 

Phototherapy. — Light  stimulates  the  nerve-ends,  and  thus 
enhances  nutritive  activity.  If  a  man  is  brought  from  dark- 
ness into  the  light,  the  carbon  dioxid  exhaled  rises  14  per  cent.; 
or,  if  the  light  is  allowed  to  act  on  the  whole  body,  the  increase 
amounts  to  36  per  cent.  Sunlight  is  capable  of  penetrating 
the  entire  thickness  of  the  body,  as  has  been  proved  by  devel- 
oping photographs  through  the  chest.  The  violet  and  extra- 
violet,  or  actinic,  rays  of  light  have  been  utilized  for  their 
chemic  effect  in  the  treatment  of  lupus. 

Spectroscopy. — The  spectroscope  is  an  instrument  for  ex- 
amining the  various  spectra  of  different  substances.  It  consists 


LIGHT.  39 

essentially  of  one  or  more  prisms,  several  convex  lenses,  and 
brass  tubing  to  provide  a  proper  focal  distance.  Flint  glass 
has  twice  the  refractive  power  of  crown  glass.  By  dovetailing 
one  prism  of  the  flint  glass  between  two  of  the  crown  glass, 
the  refraction  of  the  latter  is  neutralized  and  the  light  passes 
through  in  straight  lines,  although  dispersed  into  its  component 
colors.  The  direct-vision  spectroscope  is  all  in  one  straight 
tube.  The  single-prism  spectroscope  consists  of  the  collimator 
tube  through  which  the  light  passes  to  the  prism,  and  from  this 
is  refracted  into  the  observing  telescope.  A  third  tube  is  some- 
times attached  so  as  to  throw  another  beam  of  light  on  the 
prism,  to  be  reflected  through  the  telescope  to  the  eye,  for  the 
purpose  of  comparison. 

Experiment. — Let  each  student  view  the  sky  through  the  direct- 
vision  spectroscope,  and  note  the  rainbow  of  colors  crossed  by  dark  lines 
(Fraunhofer's),  which  are  designated  by  letters  in  the  best  instruments. 

There  are  three  kinds  of  spectra  as  studied  with  the  spec- 
troscope: continuous,  bright  line,  and  absorption.  The  first 
is  produced  by  heating  (without  vaporization)  a  solid  or  liquid 
body,  in  the  flame  near  the  slit  of  the  spectroscope. 

Experiment. — Show  continuous  spectrum  with  platinum  wire.  The 
first  color  to  appear  is  red.  Monochromatic  light,  of  course,  yields  only 
the  image  of  the  color  present  in  the  flame. 

When  a  solid  or  liquid  is  converted  into  vapor  by  increase 
of  temperature,  the  series  of  colored  bands  is  marked  here  and 
there  by  bright  lines,  the  number  and  position  of  the  lines 
indicating  almost  at  a  glance  the  element  or  elements  present 
in  any  compound.  As  the  chlorids  of  the  metals  volatilize  more 
readily  than  do  other  metallic  salts,  it  is  customary  to  dip  the 
wire  into  strong  hydrochloric  acid  before  taking  up  the  sub- 
stance to  be  tested. 

Experiment. — Examine  first  the  spectrum  of  a  sodium  salt;  note 
the  two  bright-yellow  lines,  often  appearing  as  one  line  (D  line).  Then 
examine  and  compare  the  spectra  of  salts  of  lithium,  potassium,  and 
strontium. 

The  spectroscopic  method  of  analysis  is  not  only  very 
convenient  in  many  cases,  but  is  also  exceedingly  delicate,  re- 
vealing, as  it  does,  the  presence  of  only  V2oooooooo  grain  of 
sodium. 

When  a  substance  in  solution  or  in  the  gaseous  state  is 
interposed  between  the  slit  of  the  spectroscope  and  the  source 
of  light,  we  get  absorption-spectra:  that  is  to  say,  dark  lines 
and  bands  where  the  same  substances  held  in  the  flame  would 


40  MEDICAL  PHYSICS. 

yield  bright  lines  or  bands.  The  interposed  gas  or  liquid  seems 
to  absorb  the  corresponding  rays  of  the  same  wave-length  as 
the  rays  it  emits.  The  formation  of  absorption-spectra  is  much 
employed  in  organic  spectroscopy,  particularly  in  testing  for 
blood  and  its  derivatives. 

Experiment.  —  Study  and  describe  the  absorption-spectrum  of  a 
0.1-per-cent.  solution  of  potassium  permanganate,  in  a  narrow  test-tube 
held  between  the  slit  and  the  flame,  in  which  a  platinum  wire  is  hung. 

The  dark  lines  of  the  solar  spectrum  are  due  to  absorption 
by  the  luminous  atmosphere  of  the  sun  of  the  corresponding 
elementary  rays  in  the  solid  solar  sphere.  By  comparison  with 
the  absorption-spectra  of  terrestrial  elements,  it  has  been 
found  that  nearly  all  of  these  exist  in  the  sun,  and  in  the  same 
way  the  chemic  composition  of  many  stars  has  been  deter- 
mined. By  means  of  this  delicate  instrument  a  number  of 
rare  elements  have  been  discovered:  cesium,  rubidium,  indium, 
gallium,  thallium,  and  scandium.  A  most  practical  use  of  spec- 
trum analysis  is  the  detection  of  adulterants  and  impurities  in 
chemic  preparations. 

Double  Refraction.  —  Some  substances,  as  Iceland  spar, 
have  the  peculiar  property  of  breaking  up  a  ray  of  light  into 
separate  rays.  This  is  called  double  refraction. 

Experiment. — Make  a  pinhole  in  a  card  and  place  over  it  a  piece 
of  calcite.  Note  that  two  points  of  light  are  visible,  and  that  when  the 
spar  is  turned  around  one  point  revolves  about  the  other. 

The  ray  which  is  most  refracted  is  called  the  ordinary  ray; 
the  other,  the  extraordinary,  is  the  one  which  performs  the 
circle  about  the  first. 

Polarization. — Light  is  propagated,  as  a  rule,  in  all  direc- 
tions, perpendicularly  to  the  line  of  radiation.  When  by  the 
action  of  Iceland  spar,  selenite,  or  other  substance  the  luminif- 
erous  waves  are  made  to  vibrate  in  a  single  plane,  the  light  is 
said  to  be  polarized,  and  the  change  is  termed  polarization. 

The  Nicol  prism  is  a  modified  crystal  of  Iceland  spar,  the 
acute  angles  of  which  have  been  ground  down  to  68°  and  the 
crystal  sawed  diagonally  in  two  from  one  obtuse  angle  to  the 
other,  and  the  two  pieces  rejoined  with  Canada  balsam.  The 
balsam  is  used  to  produce  total  reflection  of  the  ordinary  ray, 
which  passes  out  at  the  side  of  the  crystal. 

Polarized  light  is  not  to  be  distinguished  by  the  unaided 
eye.  For  this  purpose  we  make  use  of  two  Nicol  prisms,  called, 
respectively,  the  polarizer  and  the  analyzer.  When  the  polar- 
izer and  analyzer  are  parallel  as  to  their  axes,  light  passes 
freely;  but,  when  the  analyzer  is  rotated  so  that  its  axis  is 


LIGHT. 


41 


at  right  angles  to  that  of  the  polarizer,  the  ray  is  quenched. 
The  polariscope  is  simply  a  combination  of  polarizer  and  ana- 
lyzer; a  polarimeter  includes  also  a  circular  scale  and  a  tube 
for  holding  solutions  to  be  examined. 


Experiment. — The  difference  between  ordinary  and  polarized  light 
can  be  illustrated  by  taking  a  string  and  two  pieces  of  cardboard  with 
a  slit  in  each.  The  string  by  itself  can  be  made  to  vibrate  in  all  direc- 
tions. When  the  boards  are  fitted  over  each  other  so  that  the  slits 


42  MEDICAL  PHYSICS. 

correspond,  the  string  can  only  vibrate  in  the  direction  of  the  super- 
imposed slits.  When  the  slit  of  one  board  is  at  right  angles  to  that  of 
the  other,  all  vibration  is  stopped. 

Many  transparent  bodies  are  optically  active, — i.e.,  rotate 
a  ray  of  polarized  light  to  the  right  or  the  left, — so  that  the 
analyzer  must  be  moved  a  certain  number  of  degrees  farther 
either  way  in  order  to  shut  off  the  ray  of  light  from  the  polar- 
izer. Substances  that  rotate  polarized  light  to  the  right  are 
designated  as  dextrorotatory,  and  are  indicated  by  the  sign  -fs 
those  which  exercise  the  opposite  action  are  termed  levorota- 
tory,  and  are  marked  — . 

For  medical  purposes  the  polarimeter  (saccharimeter)  is 
employed  mainly  in  the  quantitative  estimation  of  sugars  in 
solution.  The  specific  rotatory  power  of  any  substance  is  the 
angle  in  degrees  of  rotation  effected  by  a  gram  of  the  substance 
dissolved  in  1  c.c.  of  water  in  a  tube  1  dcm.  long.  The  s.r.p. 
of  cane-sugar  is-)-  66.5;  of  levulose,  — 94.4. 

Since  the  effect  of  optically-active  media  varies  with  the 
length  and  strength  of  the  different  color-waves,  it  is  neces- 
sary in  quantitative  testing  to  employ  monochromatic  light, 
usually  yellow  and  obtained  by  burning  sodium  carbonate  in 
the  flame  of  a  Bunsen  burner.  The  letter  D  used  in  polari- 
metric  formulas  signifies  the  D  line  of  the  solar  spectrum, 
which  is  the  location  of  the  sodium  bright  lines  in  the  spectro- 
scope. 

ELECTRICITY. 

The  word  electricity  is  derived  from  the  Greek  name  of 
amber,  which  was  discovered  by  Thales,  about  600  B.C.,  to 
possess  electric  properties:  i.e.,  to  attract  light  bodies  when 
rubbed.  Twenty-two  centuries  later  Gilbert,  Queen  Elizabeth's 
physician,  found  that  many  other  substances  were  electric.  In 
1670  Boyle  obtained  the  first  artificial  electric  spark.  Some- 
thing over  one  hundred  years  ago  Franklin,  by  means  of  a  kite 
and  string,  demonstrated  the  identity  of  lightning  and  electric- 
ity. The  past  quarter  of  a  century  has  seen  such  great  advance- 
ment in  the  practical  application  of  this  agent  that  there  can 
be  no  doubt  we  are  entering  an  age  of  electricity  with  the 
passing  of  the  age  of  steam. 

The  exact  nature  of  electricity  is  unknown.  It  is  believed 
to  be  a  form  of  molecular  motion  or  ether  stress  dependent 
on  atomic  rotation,  though  for  convenience  it  is  often  spoken 
of  as  a  fluid.  It  is  convertible  into  heat  and  light. 

According  to  the  manner  of  production,  electricity  is  desig- 


ELECTRICITY.  43 

nated  as  frictional  or  mechanic,  inductive,,  chemic,  thermal,  and 
vital.  Ideolectrics  is  a  general  name  for  substances  which  gen- 
erate electricity  by  friction;  anelectrics  include  non-electrics. 
Frictional  electricity  is  of  two  kinds:  positive  and  negative 
(+  and  — ).  That  produced  by  rubbing  glass  with  silk  is 
termed  vitreous,  or  positive;  that  by  friction  between  flannel 
and  resin  is  called  negative,  or  resinous. 

Experiment. — Hang  two  pith  balls  from  a  support  by  a  string  of 
silk.  Rub  sealing  wax  with  flannel  and  a  glass  tube  with  silk,  and 
charge  each  of  the  pith  balls  by  holding  the  glass  or  the  wax  near  them. 
Note  that  when  charged  alike  the  balls  repel  each  other;  when  unlike, 
they  attract. 

Induction  is  the  production  of  electricity  in  another  body 
by  the  mere  proximity  of  an  electrified  object.  The  pith  balls 
are  charged  with  electricity  in  this  way.  The  charge  is  always 
of  an  opposite  character -to  that  of  the  inductor:  thus  the  glass 
charges  the  pith  ball  negatively.  When  +  and  —  electricities 
meet  they  are  mutually  neutralized  or  discharged,  and  the  body 
affected  is  in  electric  equilibrium,  or  at  rest. 

The  following  rules  of  electric  attraction  and  repulsion 
are  important:  1.  Unlike  electricities  attract,  like  electricities 
repel,  each  other.  2.  The  total  electric  attraction  or  repulsion 
between  two  substances  equals  the  product  of  their  electric 
power.  3.  The  strength  of  electric  attraction  or  repulsion 
varies  inversely  as  the  square  of  the  distance. 

The  electric  machine  is  an  apparatus  for  storing  up  elec- 
tricity produced  by  friction  between  a  circular  glass  plate  and 
silk,  leather,  paper,  or  amalgam.  Induction  or  influence  ma- 
chines are  generally  employed  nowadays  in  place  of  the  former 
machine.  In  these  the  plates  are  provided  with  small  pieces 
of  tinfoil,  and  are  made  to  revolve  near  each  other  in  opposite 
directions.  Plate  machines  are  affected  by  weather  changes, 
as  moisture  conducts  away  the  stored  electricity. 

Electricity  is  distributed  only  on  the  surface  of  bodies, — 
equally  on  a  sphere,  but  mostly  at  the  ends  of  other  objects: 
the  +  electricity  at  one  end,  the  —  electricity  at  the  other. 
Condensers,  or  accumulators,  are  designed  to  hold  a  large 
amount  of  electricity  in  a  small  space,  and  depend  upon  the 
principle  that  the  capacity  of  an  object  to  hold  electricity  is 
increased  by  the  proximity  of  another  insulated  object  oppo- 
sitely charged.  The  Leyden  jar  is  a  familiar  example.  When 
thus  stored  up  in  waiting  for  liberation,  electricity  is  termed 
static;  when  in  motion,  dynamic. 

The  passage  of  electricity  from  one  point  to  another  takes 
place  by  conduction  and,  to  a  less  extent,  by  aerial  convection. 


MEDICAL  PHYSICS. 


Metals,  as  a  class,  are  good  conductors,  silver  standing  first, 
with  copper  a  close  second.  Very  poor  conductors  are  called 
insulators,  or  dielectrics.  Such  are  glass,  rubber,  dry  wood, 


Fig.  13.— Electrostatic  Machine. 

air,  and  silk.  Water  is  a  better  conductor  than  air,  the  con- 
ducting-power  of  which  decreases  with  increase  of  temperature. 
The  human  body,  particularly  the  skin,  is  a  poor  conductor  of 
electricity,  the  average  resistance  being  about  1000  ohms. 


ELECTRICITY.  45 

Electricity  escapes  more  readily  from  points  than  from  smooth 
surfaces;  hence  the  use  of  the  combs  on  the  condensers  of 
some  electric  machines,  and  also  the  principle  of  the  lightning- 
rod,  which  is  meant  to  bring  together  quietly  and  gradually 
the  opposite  electricities  of  earth  and  sky. 

Atmospheric  electricity  is  generally  static,  and  is  due  to 
vegetation,  to  evaporation,  and  to  the  friction  of  the  wind  on 
the  ground.  It  is  distributed  mostly  in  open  spaces,  and  is 
most  abundant  about  noon.  It  is  either  positive  or  negative: 
the  former  always  when  the  air  is  quite  clear. 

Lightning  is  the  electric  discharge  from  the  positively 
(usually)  charged  clouds  to  the  earth,  on  which  negative  elec- 
tricity has  been  induced.  The  flash  itself  depends  on  atmos- 
pheric resistance.  The  forms  of  lightning  in  order  of  fre- 
quency are  sheet,  linear,  heat  (too  far  away  to  hear  thunder: 
more  than  fifteen  miles),  and  globe.  The  course  of  lightning 
is  generally  zigzag,  on  account  of  the  varying  resistance  tor  its 
passage  through  different  atmospheric  strata.  The  earth  is  the 
great  common  reservoir  of  electricity,  and  occasionally  light- 
ning ascends  from  the  ground  to  the  clouds  when  the  latter 
are  negatively  charged. 

The  effects  of  lightning  on  human  beings  are  those  of 
artificial  electricity,  namely:  burns,  escape  of  blood  from  the 
vessels,  shock,  deafness,  blindness,  paralysis,  and  sudden  death 
from  hemorrhage  into  the  medulla.  Persons  at  some  distance 
from  the  spot  where  a  "lightning-stroke"  occurs  often  suffer 
from  what  is  styled  the  return-shock.  That  is,  on  the  approach 
of  the  electric  force  from  the  clouds  the  body  becomes  charged 
by  induction  with  the  opposite  kind  of  electricity,  which  is 
suddenly  lost  when  the  terrestrial  and  atmospheric  charges 
neutralize  each  other.  Fulguration  is  a  term  applied  to  the 
effects  of  lightning;  sideration,  to  the  effects  of  electric  cur- 
rents. 

Static  electricity  is  used  to  some  degree  for  medical  pur- 
poses. It  has  one  advantage  over  other  kinds  of  electricity, 
and  that  is  its  greater  tension  or  penetrating  power  or  capacity 
of  overcoming  resistance;  it  can  be  administered  through  the 
clothing. 

Experiment. — Show  electric  spark  by  means  of  a  file,  and  the 
copper  wires  attached  to  a  battery.  The  duration  of  each  spark  is  from 
23  to  46  ten-millionths  of  a  second. 

Galvanic,  or  voltaic,  electricity  is  that  form  produced  by 
chemic  action.  A  galvanic  cell  consists  of  a  chemic  solution, 
usually  an  acid  mixture,  in  which  are  placed  two  (or  three) 


46  MEDICAL  PHYSICS. 

plates,  the  upper  ends  of  which  are  connected  by  copper  wires. 
The  plates  must  differ  in  susceptibility  to  the  chemic  action  of 
the  fluid.  The  one  that  is  more  acted  on  is  called  the  positive 
plate;  the  other,  the  negative.  In  medical  electric  apparatus 
zinc  is  usually  employed  for  the  +  plates;  gas  carbon  for  the 
negative.  The  wire  attached  to  the  +  plate  is  termed  the  - 
rheophore,  and  its  end  the  —  pole  (cathode)  or  electrode;  that 
attached  to  the  —  plate  is  the  +  pole  (anode)  or  electrode. 

Experiment. — Construct  a  simple  galvanic  cell  with  a  piece  each  of 
zinc  and  carbon  in  a  dilute  acid.  Connect  the  plates  with  copper  wires, 
and  note  that  chemic  action  is  more  marked  when  the  ends  of  the 
wires  are  made  to  touch  each  other. 


Fig.  14.— A  Galvanic  Cell. 

The  electricity  generated  by  chemic  action  at  the  -f-  plate 
seems  to  flow  in  a  circle  or  current  from  the  zinc  to  the  carbon 
and  thence  over  the  wires  to  the  zinc  plate  again.  When  the 
two  wires  are  joined,  the  circuit  is  said  to  be  closed;  when 
separated,  the  circuit  is  open.  Making  and  breaking  the  cir- 
cuit is  another  way  of  expressing  the  same  thing. 

A  battery  is  simply  a  combination  of  galvanic  cells.  The 
arrangement  of  the  cells  in  a  galvanic  battery  varies  with  the 
particular  use  desired.  For  medical  purposes  the  cells  are  con- 
nected in  series,  or  tandem:  i.e.,  the  carbon  of  one  cell  to  the 
zinc  plate  of  the  next.  They  are  linked  here  for  intensity — 
to  overcome  high  external  resistance,  namely:  that  of  the  skin. 


ELECTRICITY.  47 

When  the  internal  resistance — that  of  the  battery-fluid — is 
comparatively  great,  the  cells  are  linked  for  quantity,  carbon 
to  carbon  and  zinc  to  zinc;  this  arrangement  is  known  also  as 
parallel,  abreast,  or  in  multiple  arc. 

The  battery-fluid,  or  electropoion,  most  commonly  used 
consists  of  2  drams  of  bisulphate  of  mercury  dissolved  in  a 
pint  of  water,  to  which  is  added  3  ounces  of  powdered  dichro- 
mate  of  sodium  and  then  slowly  3  fluidounces  of  commercial 
sulphuric  acid.  The  office  of  the  sodium  salt  is  to  unite  with 


Fig.  15.— Faure's  Modification  of  the  Plante  Storage  Cell. 

the  hydrogen  set  free  from  the  acid  in  the  action  of  the  latter 
on  the  zinc.  When  hydrogen  is  not  taken  up  in  this  way  bub- 
bles of  the  gas  soon  form  a  coating  on  the  carbon  plate,  inter- 
fering with  the  passage  of  the  current.  Silver-chlorid  and 
other  dry-cell  batteries  are  coming  into  increasing  use,  because 
of  their  convenience  and  portability. 

In  the  storage,  or  secondary,  battery  plates  of  sheet-lead 
are  immersed  in  dilute  sulphuric  acid,  the  dichromate  being 
omitted.  A  current  of  electricity  is  passed  through  from  £he 
ordinary,  or  primary,  battery.  Hydrogen  collects  on  one  plate 


48  MEDICAL  PHYSICS. 

and  oxygen  on  the  other.  The  charge,  or  polarity,  thus  pro- 
duced remains  for  several  weeks.  Connecting  the  plates  yields 
a  current  of  a  strength  about  double  that  of  a  primary  cell, 
and  opposite  in  direction.  Storage  batteries  are  also  made  from 
red  lead  rolled  up  together  with  two  perforated  lead  sheets, 
with  flannel  between,  and  immersed  in  dilute  sulphuric  acid. 
Metallic  lead  collects  on  the  cathode  and  the  peroxid  of  lead 
on  the  anode  through  chemic  decomposition  when  the  current 
is  on. 

Flaws  or  impurities  in  the  zinc  plates  of  a  galvanic  battery 
lead  to  the  formation  of  local  currents  that  tend,  of  course,  to 


Fig.  16. — Horizontal  Mil-am-meter. 

weaken  the  main  flow.  To  obviate  this  defect  it  is  customary 
to  coat  the  zinc  with  quicksilver,  which  forms  a  smooth  amal- 
gam, and  thus  prevents  the  local  action  mentioned.  The  bisul- 
phate  of  mercury  in  the  formula  given  above  will  keep  the  zinc 
plates  well  amalgamated.  A  rusty  surface  impedes  the  passage 
of  the  current,  and  care  should  be  taken  not  to  let  the  acid  fluid 
come  into  contact  with  the  external  parts  of  the  battery. 

The  electric  current  is  the  result  of  a  difference  in  poten- 
tial (charge)  of  different  bodies  or  parts  of  a  body:  much  on 
the  same  principle  as  that  "water  seeks  its  level."  The  elec- 
tromotive force  (E.M.F.),  or  tension,  is  the  total  electric  energy 
arising  from  a  difference  in  potential.  The  volt  is  the  unit  of 


ELECTRICITY.  49 

K.M".F.  It  is  about  equal  to  the  power  of  a  Daniell  cell,  or  one- 
half  the  power  of  a  Grenet  cell.  The  actual  working  strength 
of  a  current  varies  inversely  as  the  length  and  directly  as  the 
square  of  the  diameter  of  the  conducting-wire.  The  unit  of 
resistance  is  called  the  ohm,  and  is  equal  to  the  resistance,  at 
f.p.,  of  a  column  of  mercury  of  uniform  thickness  106.3  cm. 
in  length  and  weighing  14.45  gm.;  or  to  that  of  a  copper  wire 
250  feet  long  and  1/20  inch  in  diameter.  The  resistance  of  the 
Atlantic  cable  is  700  ohms. 

The  unit  of  actual  current  is  called  an  ampere  (weber), 
and  is  equal  to  a  volt  of  E.M.F.  passing  through  an  ohm  of 
resistance.  For  medical  purposes  the  ampere  is  divided  into 
thousandths, — i.e.,  milliamperes, — of  which  from  1  to  100  or 
more  may  be  administered,  according  to  the  special  indications. 
The  milliamperemeter  is  an  instrument  for  measuring  current- 
strength  in  the  medical  application  of  electricity.  It  consists 
essentially  of  a  magnetic  needle,  around  which  the  conducting- 
wire  is  made  to  pass.  The  degree  of  deflection  of  the  needle 
thus  occasioned  (by  induction)  indicates  the  exact  strength  of 
the  current.  The  current  is  regulated,  decreased,  or  increased 
by  the  introduction  of  more  or  less  of  a  poor  conducting  mate- 
rial, as  charcoal  or  water,  or  coils  of  German-silver  wire,  known 
technically  as  a  rheostat. 

Other  units  used  in  electric  measurements  are  as  follows: 
The  coulomb,  or  unit  of  quantity,  the  force  of  a  dyne  at  1  cm., 
is  an  ampere-second:  i.e.,  a  current  of  an  ampere  in  one  second 
of  time.  The  farad  of  static  electricity  is  equivalent  to  a 
coulomb.  The  watt,  or  unit  of  total  electric  energy,  represents 
the  product  of  the  voltage  and  amperage,  and  is  equivalent  to 
V?46  horse-power. 

The  effects  of  the  galvanic  current  are  physic,  chemic,  and 
physiologic.  Heat,  light,  sound,  and  mechanic  motion  may  be 
produced  by  a  sufficiently  strong  current.  One  of  the  most  in- 
teresting of  chemic  effects  is  that  of  electrolysis,  or  decompo- 
sition of  a  substance  (usually  in  solution)  into  its  elements. 
Water,  for  instance,  is  broken  up  into  hydrogen  and  oxygen. 
When  a  salt  is  electrolyzed  the  metal,  or  alkaline  part,  or 
cation,  collects  on  the  negative  platinum  pole;  and  the  nega- 
tive, or  acid  part,  or  anion,  at  the  positive  pole.  This  fact  is 
made  use  of  in  gilding,  electroplating,  and  electrotyping. 

In  the  two  former  processes  the  object  to  be  coated  is 
suspended  from  the  —  pole  of  a  battery,  while  a  piece  of  the 
metal  desired  is  attached  to  the  +  pole,  both  being  immersed 
in  the  plating  fluid,  usually  a  solution  of  the  cyanid  of  the 
metal  in  question.  When  the  current  is  set  in  operation  the 


50 


MEDICAL  PHYSICS. 


dissolved  substance  is  decomposed,  with  deposition  of  the  gold, 
silver,  or  nickel  on  the  object  attached  to  the  pole. 

Electrotypes  are  made  much  as  follows:  An  impression  is 
made  with  the  lines  of  type  in  melted  wax,  which  is  then  coated 
over  with  powdered  graphite.  The  mold  is  then  suspended 
from  the  —  pole  in  an  acid  bath  of  cupric  sulphate,  containing 
also  a  copper  plate  hanging  from  the  +  P°le-  The  passage  of 
the  current  acts  in  the  same  manner  as  for  electroplating.  The 
process  of  photogravure  also  depends  on  electrolysis  and  on  the 
fact  that  potassium  dichromate  in  a  gelatin  film  is  not  soluble 
after  being  acted  upon  by  light. 


Fig.  17.— Electrolysis. 

Experiment. — Decompose  potassium  iodid  solution  containing  a 
little  boiled  starch  by  means  of  electrolysis.  Note  the  blue  color  pro- 
duced by  the  action  of  free  iodin  on  the  starch. 

Experiment. — Make  a  "tin  tree"  by  electrolysis,  using  a  solution 
of  stannous  chlorid  acidulated  with  hydrochloric  acid.  On  which  pole 
do  the  tin  crystals  collect? 

The  galvanic,  or  constant  current,  as  it  is  often  called,  is 
much  used  in  medicine,  especially  to  stimulate  and  exercise  by 
contractions  paralyzed  muscles,  in  this  way  preventing  atrophy 
until  Nature  restores  the  nervous  connections.  Electrotonus  is 
the  name  applied  to  the  increase  of  the  normal  nerve-current 
induced  by  the  passage  of  a  galvanic  current  along  the  nerve. 


ELECTRICITY.  51 

Both  the  normal  nerve-current  and  the  electrotonic  condition 
are  shown  by  the  galvanoscope  or  galvanometer  (milliampere- 
meter).  In  electrotonus  the  excitability  of  the  nerve  in  the 
neighborhood  of  the  positive  pole  is  decreased  (anelectrotonus), 
whereas  at  the  negative  pole  it  is  augmented  (catelectrotonus). 
Hence,  if  an  excitant  action  is  desired  the  cathode  is  placed 
over  the  part;  if  a  sedative,  the  anode  is  applied. 

The  electric  reaction  of  the  nerves  (and  the  muscles  they 
supply)  originating  at  or  below  a  spinal  lesion  is  rapidly  dimin- 
ished and  soon  lost  from  degeneration  due  to  trophic  changes. 
In  central,  or  brain,  paralysis,  on  the  other  hand,  the  response 
of  the  nerves  and  muscles  on  the  paralyzed  side  is  not  less 
marked  than  on  the  sound  side.  Normally  the  greatest  effect 
is  elicited  on  cathodic  closing  and  anodic  opening  of  the  cir- 
cuit, but  in  the  degenerative  condition  just  mentioned  the  op- 
posite phenomena  obtain:  i.e.,  the  contractions  are  greatest  on 
anodic  closing  and  cathodic  opening.  Such  an  alteration  is 
termed  the  reaction  of  degeneration. 

In  employing  the  constant  current  for  a  stimulant  effect 
on  muscles  and  nerves  it  is  customary  to  lessen  resistance  by 
using  a  rather  large  sponge  electrode  moistened  with  water  or 
brine.  The  sponge  is  used  dry  when  the  stimulus  is  to  be  con- 
fined to  the  skin.  This  current  has  no  effect,  except  elec- 
trolysis, in  the  period  between  the  make  and  the  break.  It 
should  be  turned  on  gradually  to  the  required  dosage;  the 
seance  may  last  from  one  to  ten  minutes,  and  then  the  current 
should  be  turned  off  slowly,  thus  avoiding  annoying  shock  to 
the  patient.  Four  hundred  volts  may  kill  an  animal  by  the 
muscular  contractions  generating  a  large  amount  of  heat.  Sev- 
eral thousand  volts  may  produce  fatal  shock  (electrocution). 

Another  common  medical  use  of  galvanism  is  for  its  elec- 
trolytic effect  in  resolving  tumors,  strictures,  etc.  For  this 
purpose  a  suitable  metallic  electrode  attached  to  the  —  pole 
is  employed.  If  a  drying  action  is  desired,  as  in  the  case  of 
an  unhealthy  ulcer,  the  electrode  should  connect  with  the  -f- 
pole,  around  which  the  negative,  or  acid,  substances  congregate. 

Epilation,  or  the  permanent  removal  of  hair,  by  electricity 
is  an  example  of  electrolysis,  the  needle  used  to  pierce  the  hair- 
follicle  being  attached  to  the  cathode.  Cataphoresis,  or  the 
forcing  of  medicaments  into  the  tissues  by  means  of  the  con- 
stant current,  is  but  seldom  employed,  having  little,  if  any, 
advantage  over  the  ordinary  methods  of  administering  medi- 
"cines.  Electrocauterization  is  of  great  service  in  the  treatment 
of  diseased  mucous  membranes.  For  cautery  effects  the  storage 
or  secondary  battery  is  usually  selected,  on  account  of  the 


52  MEDICAL  PHYSICS. 

greater  intensity  of  its  current;  and  the  electrodes  are  of  plati- 
num, because  of  its  resistance  and  infusibility. 

Sinusoidal  alternating  currents  produce  no  chemic  effects, 
and  each  wave  moves  in  the  opposite  direction  to  the  pre- 
ceding one.  By  its  frequency  is  meant  the  number  of  waves 
per  second.  Periods  are  double  waves:  two  in  opposite  direc- 
tions. Sinusoidal  currents  of  considerable  potency  and  a 
frequency  of  100  to  200  per  second  give  rise  to  serious  and 
even  fatal  accidents,  and  are  used  for  electrocutions.  If  the 
potential  is  increased  and  the  frequency  reaches  several  hun- 
dred millions  or  several  billions,  whatever  the  voltage  the  cur- 
rent becomes  harmless.  This  strange  fact  is  comparable  with 
the  fact  that  sound  affects  the  organ  of  hearing  and  light 
that  of  sight  only  within  certain  limits  of  vibrations. 

Frictional  electricity  travels  at  the  rate  of  288,000  miles 
per  second.  In  practice  the  galvanic-current  velocity  depends 
largely  on  the  length  of  the  circuit  and  the  character  and 
area  of  the  conductor.  Nerve-currents  move  at  the  rate  of 
only  35  to  100  meters  per  second. 

Thermo-electricity  is  generated  by  heat  in  conductors  of 
relatively  small  caliber  or  in  obstructed  conductors.  While 
this  form  of  electricity  may  be  produced  in  a  single  metal,  it 
is  customary  to  solder  together  one  end  of  bars  of  two  metals, 
heating  the  bars  at  their  junction.  The  thermo-electric  pile 
consists  of  49  pairs  of  bismuth  and  antimony  bars  arranged 
in  7  rows.  The  thermo-electric  current  is  feeble,  though 
steady  and  convenient.  Other  piles  are  made  of  70  or  more 
pairs  of  iron  and  type-metal,  or  of  iron  and  galena. 

A  new  and  cheap  method  of  producing  electricity  is  that 
of  Dr.  Jacques,  who  kept  carbon  plates  in  fused  sodium  hy- 
drate at  300°,  with  the  result  that  32  per  cent,  of  the  carbon 
was  converted  into  the  electric  current. 

Vital  electricity  is  possessed  by  plants  as  well  as  animals. 
The  most  striking  example  of  animal  electricity  is  the  Gym- 
notus,  or  electric  eel  of  South  America,  which  is  said  to  give 
shocks  so  strong  as  to  stun  horses  and  cattle.  Its  electric 
apparatus  consists  of  a  series  of  prismatic  tubes  filled  with  an 
albuminous  liquid,  arranged  along  the  sides  of  the  body  and 
connected  with  a  special  lobe  of  the  brain.  The  strength  of 
a  series  of  discharges  of  vital  electricity  gradually  lessens  from 
first  to  last.  Animal  electricity  is  mainly,  if  not  wholly,  of 
the  static  variety,  usually  positive. 


MAGNETISM.  53 


MAGNETISM  AND  ELECTROMAGNETISM. 

Magnetism  is  the  property  of  attraction  or  repulsion  of 
masses  of  like  elements,  exhibited  especially  by  iron,  nickel, 
and  cobalt.  It  is  a  molecular  force  related  to  electricity.  The 
natural  magnet,  or  lodestone,  is  an  oxid  of  iron,  which  was 
first  found  in  Magnesia,  Asia  Minor;  hence  the  name  of 
magnet. 

Artificial  magnets  are  made  by  rubbing  with  the  lode- 
stone  or  with  other  artificial  magnets,  or  by  induction  from 
the  electric  current  through  a  coil  of  wire.  Temporary  mag- 
nets, like  that  of  the  faradic  battery,  are  composed  of  soft 
iron;  permanent  magnets  retain  the  power  of  attraction  for 
a  long  time,  and  are  made  of  tempered  steel.  Artificial  mag- 
nets are  of  two  forms:  the  bar  and  the  horseshoe.  The  latter 
is  generally  employed.  When  not  in  use  its  armature,  or 
keeper,  should  always  be  applied  to  prevent  the  escape  of  mag- 
netism. Compound  magnets  are  composed  of  thin  sheets  of 
steel  screwed  together;  they  are  stronger  than  simple  ones. 
The  property  of  magnetism  is  lost  at  a  red  heat. 

Experiment. — Show  the  action  of  a  bar  magnet  on  iron  filings 
placed  on  the  other  side  of  a  sheet  of  paper  and  of  a  piece  of  glass, 
proving  that  magnetism  does  not  require  the  presence  of  air.  Sift  the 
filings  on  the  paper  and  show  how  the  lines  of  magnetic  force  radiate 
in  all  directions. 

The  two  ends  of  a  magnet  are  called  its  poles.  No  matter 
how  small  the  magnet  or  into  how  many  pieces  it  may  be 
broken,  each  fragment  has  still  two  poles.  When  a  magnet 
is  freely  suspended,  one  end,  or  pole,  always  points  toward  the 
north;  the  other,  to  the  south.  A  needle  magnet  balanced 
over  a  circular  chart  constitutes  the  mariner's  compass. 

Experiment. — With  a  bar  magnet  and  a  compass  show  how  like 
poles  repel  and  unlike  attract. 

The  earth  itself  is  a  great  magnet,  its  magnetism  being 
due  probably  to  electric  currents  flowing  from  east  to  west  and 
generated  by  the  sun's  rays  (sun-spots,  northern  lights).  The 
magnetic  poles  of  the  earth  do  not  correspond  with  the  geo- 
graphic poles.  The  north  magnetic  pole  is  in  Boothia  Land 
in  70°  north  latitude;  the  south  pole  in  Victoria  Land,  75  1/2° 
south  latitude.  The  longitude  of  these  poles  shifts  from  east 
to  west  and  back  again,  the  oscillation  requiring  centuries  for 
its  completion.  At  present  the  north  magnetic  pole  is  moving 
westward  at  the  rate  of  1°  in  twelve  years.  From  these  facts 
it  is  evident  that  the  north  pole  of  the  compass  points  directly 


54  MEDICAL  PHYSICS. 

north  only  in  the  meridian  which  passes  through  the  north 
magnetic  pole.  This  meridian  is  known  as  the  line  of  no 
variation.  The  "dipping"  of  the  needle  from  the  horizontal 
increases  as  we  approach  the  magnetic  pole,,  where  it  would 
stand  vertical  were  it  not  counterpoised  by  a  weight  at  the 
opposite  pole. 

The  dual  nature  of  magnetism  is  designated  by  the  term 
polarity.  Substances,  like  iron,  that  are  attracted  by  the  mag- 
net and  arrange  themselves  axially  between  its  poles,  are  called 
paramagnetic.  Those  which  are  repelled  and  take  an  equatorial 
position  between  the  poles  are  termed  diamagnetic.  Bismuth 
is  the  foremost  example  of  this  class.  All  substances  in  the 
form  of  heated  gas  are  diamagnetic. 

Besides  the  compass,  the  chief  applications  of  permanent 
magnets  are  in  removing  pieces  of  iron  or  steel  from  the  eye, 
in  separating  magnetite  from  sand  and  crushed  rock,  and  in 
freeing  malt  and  grain  from  pieces  of  scrap-iron.  Soft  mag- 
nets are  employed  very  extensively  in  faradic  batteries  and 
electric  dynamos.  Literally,  animal  magnetism  does  not  exist. 


ELECTROMAGNETISM,   OR  ELECTRODYNAMICS. 

When  a  bar  magnet  is  placed  within  a  coil  of  wire  it  sets 
up  a  current  of  electricity  in  the  coil,  and  when  the  magnet 
is  removed  there  is  a  current  in  the  opposite  direction  to  the 
first.  Conversely,  when  a  piece  of  soft  iron  is  placed  within 
a  coil  through  which  a  current  of  electricity  is  passing,  the 
iron  becomes  magnetic.  When  one  coil  is  placed  within  or 
without  another  through  which  a  current  is  passing,  a  sec- 
ondary or  induced  current  is  produced  in  the  former:  in  the 
opposite  direction  at  the  make  of  the  primary  or  battery  cur- 
rent, in  the  same  direction  at  the  break.  In  practice  the  pri- 
mary helix,  or  coil,  is  made  short  and  thick,  so  as  to  offer  as 
little  resistance  as  possible  to  the  electric  flow.  The  secondary 
coil,  on  the  other  hand,  should  consist  of  a  long,  thin  wire, 
since,  the  longer  and  thinner  it  is,  the  greater  the  induction. 
Both  coils,  of  course,  should  be  carefully  insulated. 

Experiment. — Show  magnetic  induction  with  iron  tacks  and  mag- 
nets: how  one  tack  attached  to  the  magnet  can  be  made  to  pick  up 
another. 

The  Euhmkorff  induction-coil  consists  essentially  of  a  gal- 
vanic battery  with  its  connecting  wires,  a  secondary  helix,  a 
soft  magnet,  a  spring  interrupter,  and  a  condenser.  The  best 
coils  give  a  spark,  at  the  break,  several  feet  in  length.  The 


ELECTROMAGNETISM.  55 

faradic  battery  is  the  same  as  a  Ruhmkorff  coil  minus  the  con- 
denser. The  draw-tube  in  the  battery  is  placed  between  the 
primary  and  the  secondary  coils,  and  when  drawn  out  increases 
the  current  by  removing  obstruction  to  induction. 

The  two  faradic  currents  (primary  and  secondary)  are  also 
known  as  interrupted  currents.  The  secondary,  or  induced, 
current,  is  stronger  than  the  primary,  or  battery,  current. 
Either  current  is  much  more  intense  at  the  break  than  at  the 
make  of  the  circuit,  since  at  the  break  the  extra  current  set 
up  by  induction  between  adjacent  turns  of  the  same  coil  runs 
in  the  same  direction  as  the  principal  current,  while  at  the 
make  it  goes  against  the  main  current  and  reduces  its  force. 
As  a  nerve-stimulant  and  muscle-tonic  the  interrupted  cur- 
rent is  preferred  in  most  instances  to  the  constant  current. 
Galvanism,  however,  has  a  deeper  effect  than  faradism,  and 
hence  is  employed  in  the  treatment  of  internal  organs  and  the 
stimulation  of  paralyzed  muscles  that  do  not  react  to  the 
faradic  flow. 

The  passage  of  electricity  from  a  Ruhmkorff  coil  through 
vacuum  apparatus,  such  as  Crookes's  tubes,  gives  rise  to  a 
brilliant  display  of  violet-tinted  light,  which  is  accompanied  by 
the  invisible  x-  or  Roentgen  rays,  both  the  latter  and  the 
former  emanating  from  the  cathode.  The  x-rays  are  peculiar 
in  that  they  penetrate  many  objects  opaque  to  ordinary  light, 
such  as  wood,  paper,  and  flesh.  On  the  other  hand,  they  do 
not  pass  through  glass.  It  is  easy  to  comprehend  how  they  may 
be  made  to  form  a  shadow,  or  silhouette,  of  bodies  opaque  to 
themselves  on  a  sensitized  plate,  which  may  be  developed  as 
any  other  photographic  negative.  Sciagraphy,  or  shadow-pict- 
uring, has  already  proved  of  much  service  in  the  diagnosis  of 
bony  injuries  and  the  localization  of  foreign  bodies  in  the 
tissues.  The  fluoroscope  does  away  with  the  necessity  of  pho- 
tographic methods  in  connection  with  the  x-rays.  It  consists, 
in  the  main,  of  a  sheet  of  pasteboard  coated  with  some  fluores- 
cent material  (platino-barium  cyanid  or  tungstate  of  calcium), 
which  reveals  directly  to  the  observer's  eyes  the  shadow  of  the 
skeleton  or  of  foreign  bodies  imbedded  in  the  flesh. 

The  electric  dynamo  is  the  basis  of  nearly  all  the  practical 
industrial  applications  of  electricity.  It  consists  of  a  revolv- 
ing electromagnet,  or  armature;  and  a  fixed,  or  field,  magnet. 
Traces  of  magnetism  in  the  latter  induce  slight  currents  in 
the  armature,  and,  by  reaction  between  the  two,  currents  of 
great  strength  are  soon  produced.  The  alternating  currents 
may  be  turned  in  one  direction  by  a  simple  contrivance  called 
a.  pole-changer,  or  commutator.  The  currents  thus  produced 


56  MEDICAL  PHYSICS. 

pass  over  conducting-wires  to  be  transformed  as  desired  into 
heat,  light,  sound,  and  mechanic  motion.  The  electric  motor 
is,  practically  speaking,  the  same  as  the  dynamo.  The  move- 
ment of  the  armature  is  easily  transmitted  to  the  wheels  of 
cars  and  machinery.  "Fusible  wires'7  of  alloys  that  melt  at  a 
low  temperature  are  often  introduced  into  buildings  to  prevent 
fires  from  excessive  currents  of  electricity. 

Electric  lighting  depends  on  the  resistance  to  the  passage 
of  electricity  through  a  poor  conductor  or  one  of  small  caliber. 
The  incandescent  lamps  are  exhausted  of  air  and  contain  a 
filament  of  carbon.  The  arc  light  is  produced  by  the  resistance 
of  the  air  to  the  current  passing  between  two  adjacent  elec- 
trodes. As  most  metals  melt  quickly  in  this  terrific  heat,  the 
nearly  infusible  gas-carbon  is  employed  for  the  electrodes,  the 
sticks  being  kept  at  the  proper  distance  as  the  -f-  pole  wastes 
away,  by  an  automatic  feeding  arrangement.  Electric  light  is 


Fig.  18.— Telephone. 

most  like  sunlight  of  any  artificial  product,  and  is  also  the 
most  hygienic.  It  is  quite  rich  in  violet  and  actinic  rays. 

Electric  heating,  like  electric  lighting,  depends  on  the  re- 
sistance of  poor  conductors.  Electric  furnaces  yield  a  very 
intense  heat,  which  is  used  for  fusing  metals  and  for  reduction 
purposes,  as  in  the  extraction  of  aluminum.  Welding  of  the 
common  metals  is  done  now  very  extensively  by  electricity. 
A  new  suggestion  in  this  connection  is  the  electric  pad,  or 
permanent  poultice,  through  which  a  constant  current  is  made 
to  pass. 

The  electric  current  has  many  applications  in  apparatuses 
of  speech  and  sound,  as  exemplified  by  the  telephone,  the  mi- 
crophone, the  telegraph,  the  telautograph,  and  electric  bells, 
clocks,  and  fire-alarms.  In  each  of  these  we  have  a  combina- 
tion of  electricity  and  magnetism.  In  the  telephone,  for  in- 
stance, the  vibrations  of  the  thin  diaphragm  at  the  bottom  of 


ELECTROMAGNETISM.  57 

the  speaking-tube  set  in  motion  by  the  speaker's  voice  reacts 
on  the  bar  magnet  behind,,  and  this,  in  turn,  induces  variable 
currents  in  the  surrounding  coil  of  wire.  These  currents  trav- 
erse the  wire  to  the  connected  instrument  at  a  distance,  where 
the  series  of  changes  is  reversed:  i.e.,  the  magnet  is  affected 
by  the  current  in  the  coil  of  wire,  and  the  metallic  disk  of  the 
receiver  is  magnetized  and  drawn  nearer  and  let  go  accord- 
ingly. For  practical  use  each  instrument  contains  a  Leclanche 
cell  (ammonium  chlorid),  or  a  dry  cell,  furnishing  a  constant 
current  which  the  action  of  the  vibrating  disk  on  the  magnet 
merely  modifies.  For  long-distance  conversations,  as  between 
different  cities,  powerful  induction-coils  are  employed  to  fur- 
nish the  current. 

In  the  telegraph  (Morse,  1837)  pressing  the  key  at  one 
office  closes  the  circuit.  When  the  finger  is  removed  a  spring 
pulls  the  key  up.  In  the  receiving  office  when  the  circuit  is 
closed  the  key  here  is  magnetized  and  drawn  down  upon  the 
sounder;  when  the  circuit  is  broken  it  springs  up  again,  and 
thus  the  succession  of  clicks,  or  dots  and  dashes  as  shown  on 
paper,  is  repeated  by  the  instrument  receiving  the  message. 
The  earth  itself  is  the  best  conductor  of  electricity,  so  that 
one  line  of  wire  is  made  to  suffice  for  telegraphic  communica- 
tion, the  wire  being  grounded  at  either  terminus.  In  trans- 
mitting messages  long  distances  the  strength  of  the  current 
is  diminished  so  much  that  it  is  unable  to  move  the  sounder 
audibly.  This  difficulty  is  overcome  by  means  of  repeaters  or 
relays,  electromagnets  wound  with  long,  thin  wire,  used  to 
close  the  circuit  of  the  local  battery.  Wireless  telegraphy  de- 
pends on  the  Hertzian  waves  of  ether,  or  high-potential  elec- 
tricity. The  apparatus  consists  of  a  vertical  insulated  wire; 
a  transmitter,  including  a  Euhmkorff  coil  and  two  sparking 
rods  with  a  brass  ball;  and,  last,  a  receiver  composed  of  two 
silver  plugs  in  a  glass  tube,  along  with  a  mixture  of  nickel  and 
silver  filings.  Electric  bells,  clocks,  and  fire-alarms  act  by  the 
induction  of  a  closed  circuit  on  a  soft  magnet,  which,  in  turn, 
sets  in  motion  wheels,  hands,  or  striking-springs. 

The  so-called  electric  belts,  brushes,  clothing,  etc.,  are 
utterly  useless  and  worthless.  Obviously  even  theoretically 
they  can  return  to  the  body  only  the  electricity  they  have 
derived  from  it  by  simple  friction  or  by  a  slight  chemic  action 
with  the  acid  perspiration. 

Experiment. — Put  a  coin  below  the  tongue  and  a  piece  of  zinc 
above.  Note  sharp  twinge  and  metallic  taste  when  the  two  touch. 


58  MEDICAL  PHYSICS. 

CRYSTALLOGRAPHY. 

Most  inorganic  and  many  organic  substances  when  assum- 
ing the  solid  state  from  fusion,  solution,  or  sublimation  tend 
to  take  on  a  symmetric  geometric,  or  crystalline,  form.  The 
liquid  and  gaseous  states  aid  crystallization  by  allowing  the 
molecules  to  arrange  themselves  in  order  around  the  axes  or 
lines  of  growth:  i.e.,  certain  imaginary  lines  in  which  cohesive 
force  is  greatest.  Crystals  by  fusion  are  said  to  be  formed  in 
the  dry  way;  when  from  solution,  in  the  moist  way.  The 
largest  and  most  perfect  crystals  are  those  produced  by  Nature 
in  the  gradual  evaporation  of  aqueous  solutions  of  mineral 
salts.  The  process  of  crystallization  can  be  hastened  by  im- 
mersing in  the  liquid  strings,  chips,  and  other  foreign  objects 
to  serve  as  nuclei  of  growth.  Kock-candy  and  milk-sugar  are 
prepared  in  this  manner. 

Experiment. — Make  a  saturated  solution  of  alum,  and  hang  in  it 
a  piece  of  twine.  When  the  liquid  has  cooled  the  excess  of  siibstance 
above  its  solvent  power  at  the  lower  temperature  will  be  found  as 
crystals  on  the  cord.  The  formation  of  the  beautiful  frost  patterns 
on  the  windows  in  winter  is  another  illustration  of  the  same  facts. 

The  forms  of  crystalline  matter  are  quite  numerous,  yet 
they  can  be  classified  in  six  simple  systems,  namely:  the 
monometric,  dimetric,  trimetric,  monoclinic,  triclinic,  and 
hexagonal. 

The  monometric  (regular,  isometric)  system  has  three 
axes  which  are  equal  in  length  and  at  right  angles  to  each 
other.  The  primary  type  of  this  system  is  the  cube,  exem- 
plified by  iron  pyrites.  The  regular  octahedron  (magnetite, 
diamond)  and  regular  pyramid,  or  tetrahedron  (fluorspar, 
tetrahedrite),  are  derived  from  the  cube  by  truncation  of  its 
solid  angles. 

The  dimetric,  or  tetragonal,  system  has  also  three  axes 
at  right  angles  to  each  other,  but  one  of  them  is  shorter  than 
the  other  two.  The  two  types  of  this  system  are  the  square 
pyramid,  or  acute  octahedron  (octahedrite),  and  the  square 
prism  or  column  (wernerite). 

In  the  trimetric,  or  orthorhombic,  system  the  three  axes 
are  perpendicular  to  each  other,  but  are  all  of  unequal  length. 
The  varieties  are  the  rhombic  and  rectangular  prisms  and 
pyramids.  Examples  of  substances  belonging  to  this  system 
are  sulphur  (rhombic  octahedron),  topaz  (right  rhombic  prism), 
and  andalusite  (right  rectangular  prism). 

The  monoclinic,  or  oblique,  system  has  three  unequal 
axes,  like  the  trimetric  system,  from  which  it  differs  by  the 


CRYSTALLOGRAPHY. 


59 


vcrtic  axis  being  set  obliquely  to  the  other  two,  instead  of 
perpendicularly.  The  oblique  pyramid  (feldspar)  and  prism 
(orthoclase,  rectangular;  titanite,  rhombic)  are  the  subdivis- 
ions. 

The  triclinic,  or  doubly  oblique,  system  has  three  axes  no 
two  of  which  are  at  right  angles  to  each  other.  The  doubly 
oblique  pyramid  (copper  sulphate),  doubly  oblique  prism  (chal- 
canthite),  and  doubly  oblique  octahedron  (axinite)  illustrate 
this  system. 

The  hexagonal,  or  rhombohedral,  system  has  four  axes, 
three  of  which  are  in  the  same  plane  at  angles  of  60°  with  each 
other;  the  fourth  is  perpendicular  to  the  other  three.  The 


Fig.  19.— Systems  of  Crystallization. 


hexagonal  prism  (apatite)  is  the  primary  form.  From  it  the 
hexagonal  pyramid  (quartz)  is  obtained  by  truncation  of  the 
angles  of  one  end;  the  rhombohedron,  or  scalenohedron  (cal- 
cite),  by  truncation  of  the  alternate  angles  of  either  end. 

When  two  substances  crystallize  in  the  same  form  they  are 
said  to  be  isomorphous.  Potassium  iodid  and  sodium  chlorid, 
for  instance,  both  crystallize  as  cubes.  Isomorphous  compounds 
frequently  contain  the  same  number  of  atoms.  A  substance 
which  crystallizes  in  two  or  more  systems  is  termed  dimorphous 
or  polymorphous.  Sulphur  is  dimorphous  (rhombic  octahedron 
and  monoclinic  prisms).  Non-crystalline  substances  are  called 
amorphous:  that  is,  without  definite  form.  An  allotropic  ele- 


60  MEDICAL  PHYSICS. 

ment  is  one  that  exists  in  two  or  more  crystalline  or  amorphous 
states,  each  with  different  physic  properties.  Carbon,  for  ex- 
ample, is  met  with  as  charcoal,  plumbago,  and  diamond. 

A  characteristic  of  many  crystalline  rocks  is  that  of  cleav- 
age, which  means  the  property  of  splitting  readily  in  one  direc- 
tion into  natural  layers.  Mica  furnishes  a  good  example  of 
this  peculiarity. 

The  greater  number  of  crystalline  substances  are  combined 
chemically  with  water,  termed  the  water  of  crystallization;  and 
to  this  the  various  colors  of  most  crystals  are  due.  The  com- 
bination may  be  molecule  for  molecule, — that  is,  one  of  water 
to  one  of  the  solid  substance;  oftener,  however,  the  water- 
molecules  much  exceed  in  number  those  of  the  mineral  matter. 
Alum,  for  example,  has  24  molecules  of  water  to  1  of  the  salt 
proper.  A  few  compounds,  as  silver  nitrate,  crystallize  with- 
out any  water  in  their  composition;  hence  are  called  anhydrous. 
Some  substances  take  up  more  or  fewer  molecules  of  water  of 
crystallization  according  as  the  process  is  conducted  at  a  lower 
or  higher  temperature;  the  resulting  crystals  in  such  an  event 
often  differ  from  each  other  in  size  and  shape.  Sodium  car- 
bonate crystallizes  at  ordinary  temperatures  with  10  molecules 
of  water  in  oblique  rhombic  prisms;  at  higher  temperatures 
with  8  or  5  of  water;  from  boiling  solutions  as  rectangular 
plates  with  1  of  water.  The  chemic  union  between  the  water 
of  crystallization  and  the  remainder  of  the  crystal  is  a  very 
weak  one,  and  is  broken  up  in  most  instances  by  heating  the 
crystals  to  the  b.p.  of  water. 

Experiment. — Heat  a  crystal  of  copper  sulphate  carefully  in  a 
porcelain  dish,  and  note  disappearance  of  color  along  with  the  water 
of  crystallization.  Continue  the  heating  until  a  dry  white  powder  is 
left  and  allow  to  cool.  Then  place  the  powder  in  the  palm  and  add  a 
little  cold  water.  The  blue  color  is  restored,  and  considerable  heat  is 
produced  (chemic  action). 

Some  crystalline  drugs  (sodium  compounds)  lose  their 
water  of  crystallization  gradually  on  simple  exposure  to  dry 
air.  These  bodies  are  designated  as  efflorescent. 

On  the  difference  in  solubility,  and  hence  the  temperature 
at  which  crystalline  solidification  takes  place,  depends  the 
separation  of  substances  by  fractional  crystallization,  the  least 
soluble  substance  crystallizing  first  out  of  the  cooling  or  con- 
centrating solution.  In  this  way  common  salt  is  prepared  from 
sea-water,  the  more  soluble  salts  remaining  in  solution  in  the 
mother-liquor,  or  bittern. 

Another  use  of  crystallization  is  in  purifying  medicines, 
as  foreign  matters  are  dissociated  to  a  large  degree  during  the 


OSMOSIS  AND  DIALYSIS.  61 

formation  of  crystals.  Hence,  ice  is  purer  than  the  water  from 
which  it  was  formed.  In  chemic  microscopy  the  ability  to  rec- 
ognize the  crystalline  forms  characteristic  of  various  compounds 
is  of  the  greatest  practical  importance. 

OSMOSIS  AND  DIALYSIS. 

Osmosis  signifies  the  stream  of  water-molecules  passing 
through  a  membrane;  dialysis,  the  passage  of  the  molecules 
of  a  dissolved  substance.  When  pure  water  and  an  aqueous 
solution  of  a  salt  are  separated  by  a  semipermeable  membrane 
(one  which  allows  water,  but  not  the  salt,  to  pass,  such  as 
finely-divided  potassium  ferrocyanid  deposited  in  fine-grained 
porcelain),  the  osmotic  pressure  is  greater  toward  the  side  of 
the  salt  solution,  the  dissolved  molecules  of  the  salt  seeming 
in  a  manner  to  screen  the  membrane  from  contact  with  a  cer- 
tain number  of  water-molecules.  The  osmotic  pressure  varies 
directly  with  the  concentration  of  the  solution  (molecules  or 
ions),  and  the  highest  hydrostatic  pressure  thus  exerted  has 
been  proved  equal  to  that  caused  by  as  many  molecules  of  gas 
as  in  that  of  the  crystalloid  in  solution,  if  confined  in  the  same 
space  at  the  same  temperature.  Solutions  of  substances  con- 
taining the  same  number  of  molecules  and  ions  in  a  given 
volume  exert  the  same  osmotic  pressure,  and  are  said  to  be 
isohydric. 

Most  inorganic  substances  when  in  solution  break  up  or 
dissociate  into  two  or  more  parts  known  as  ions,  and,  the 
greater  the  dilution,  the  more  complete  the  dissociation  (quite 
complete  at  about  Viooo  normal).  Such  substances  are  called 
electrolytes.  Thus,  sodium  chlorid  dissolved  in  water  disso- 
ciates more  or  less  into  the  positively  charged  cation  sodium 
and  the  negatively  charged  anion  chlorin.  Sugar,  on  the  other 
hand,  though  soluble  and  crystalloid,  is  a  non-electrolyte.  The 
liberated  ions  are  charged  with  electricity,  and  it  is  they  that 
carry  the  current  from  plate  to  plate.  In  osmotic  pressure 
ions  are  of  equal  value  to  molecules;  hence,  the  more  the  dis- 
sociation, the  greater  the  pressure. 

The  osmotic  pressure  of  non-electrolytes  in  solution  is 
readily  calculated  by  comparing  gram-molecular  solutions  (con- 
taining the  molecular  weight  of  the  substance  in  grams  per 
liter)  with  the  pressure  required  to  compress  the  gram-mole- 
cule of  hydrogen  (2)  to  a  liter.  Thus,  a  gram-molecular  solu- 
tion of  cane-sugar  contains  342  gm.  per  liter,  and  it  contains 
as  many  molecules  as  2  gm.  of  hydrogen.  Now,  1  gm.  of 
hydrogen  at  the  pressure  of  1  atmosphere  (760  mm.  of  mer- 


62  MEDICAL  PHYSICS. 

cury)  occupies  a  volume  of  11.16  liters;  hence  2  gm.  occupy 
twice  this  volume,  or  22.32  liters.  To  compress  the  latter 
volume  to  a  liter  requires  a  pressure  of  22.32  atmospheres. 
A  gram-molecular  solution  of  cane-sugar  (or  any  other  non- 
electrolyte)  would  therefore  exert  an  osmotic  pressure  of  22.32 
atmospheres;  a  10-per-cent.  solution,  yio  of  22.32,  or  2.23 
atmospheres  (1694.8  mm.  of  mercury).  In  calculating  the 
osmotic  pressure  of  electrolytes  by  this  method  one  would  need 
to  know  what  proportion  of  the  substance  in  solution  had  dis- 
sociated into  ions. 

In  the  case  of  electrolytes  a  very  convenient  method  of 
determining  osmotic  pressure  is  by  means  of  the  f.p.  As 
already  stated,  this  is  lowered  by  the  presence  of  salts  in  solu- 
tion, and  the  lowering  has  been  proved  to  be  proportional  to 
the  number  of  molecules  and  ions  in  a  given  volume:  a  fact 
which  holds  good  as  well  with  osmotic  pressure.  The  amount 
of  depression  in  centigrade  degrees  and  fractions  below  the 
f.p.  of  pure  water  is  ascertained  by  means  of  a  delicate  dif- 
ferential thermometer,  and  is  usually  expressed  by  the  symbol 
A.  A  gram-molecular  solution  of  any  non-electrolyte  lowers 
the  f.p.  1.87°  C.;  hence  the  osmotic  pressure  of  a  given  solu- 
tion can  be  expressed  directly  by  dividing  the  constant  1.87 
into  the  A  of  latter.  Thus,  the  A  of  blood-serum  is  0.56;  this 
divided  by  1.87  gives  0.3;  and  0.3  of  22.32  =  6.696  atmos- 
pheres, the  equivalent  of  the  osmotic  pressure  of  blood-serum. 

From  the  physic  standpoint  an  isotonic  or  isomotic  solu- 
tion is  one  having  an  osmotic  pressure  equal  to  that  of  blood- 
serum — 0.95-per-cent.  common  salt,  for  instance;  a  hypertonic 
solution  exerts  a  higher,  and  a  hypotonic  solution  a  lower, 
pressure  than  does  serum. 

The  great  difference  in  the  rate  of  membranous  diffusion 
of  crystalloids  and  colloids  makes  the  separation  of  one  class 
from  the  other  an  easy  matter.  The  dialyzer,  an  instrument 
for  this  purpose,  consists  of  a  round  glass  vessel  open  at  the 
upper  and  narrower  end,  and  closed  at  the  bottom  with  a  piece 
of  parchment-paper.  The  mixed  solution  is  placed  in  the  dia- 
lyzer, and  the  whole  immersed  to  a  slight  depth  in  distilled 
water  for  12  or  24  hours.  At  the  end  of  this  time  the  crystal- 
loid substance  will  be  found,  for  the  most  part,  in  the  water 
exterior  to  the  vessel,  while  the  colloid  material  still  remains 
within.  A  few  amorphous  substances  (peptons)  are  crystalloid. 

The  process  of  dialysis  is  of  greatest  service  in  toxicology, 
in  the  separation  of  crystalloid  poisons  from  food  and  other 
stomach-contents.  It  is  also  used  to  some  extent  in  the  prepa- 
ration of  drugs. 


SOUND.  63 

Experiment. — Place  a  copper  sulphate  solution  and  some  white  of 
egg  into  a  dialyzer,  and  let  stand  until  the  next  day.  The  blue  color 
of  the  copper  salt  now  shows  without  as  well  as  within  the  vessel,  but 
the  albumin  has  not  diffused:  the  liquid  within  the  vessel  coagulates 
on  boiling,  while  that  without  does  so  hardly  at  all. 


SOUND. 

Sound  consists  in  vibrations  of  the  air  or  of  sonorous 
(elastic)  substances  perceptible  to  the  sense  of  hearing.  The 
science  of  sounds  is  known  as  acoustics. 

Experiment. — Fit  a  large  test-tube  with  a  tight  cork  fitted  with  a 
short-pointed  glass  tube.  Place  a  few  granules  of  zinc  in  the  bottom 
of  the  test-tube,  and  cover  them  with  an  inch  or  two  of  dilute  sulphuric 
acid.  The  gas  hydrogen  is  evolved.  After  a  few  minutes,  when  all  the 
contained  air  has  escaped,  light  the  gas,  and  hold  the  flame  in  the  mouth 
of  a  glass  cylinder  about  an  inch  wide.  On  adjusting  the  flame  to  the 
right  point  in  the  tube  a  loud  tone  is  produced  by  the  vibrations  of 
heated  air  in  the  cylinder.  Sounds  can  also  be  produced  by  an  inter- 
mittent beam  of  sunlight  playing  on  colored  worsted  or  lamp-black  in 
a  glass  tube. 

Experiment. — Place  a  watch  on  cotton-wool  under  the  air-pump, 
and  create  a  vacuum.  The  ticking  becomes  fainter,  and  is  finally  im- 
perceptible. 

Sound  is  transmitted  by  spheric  waves  or  undulations,  at 
the  rate  in  air  of  about  1/.  mile  per  second  (1125  feet  at  60° 
F.);  in  water  4  times  as  fast;  in  iron  16  times  as  fast.  In 
gases  the  velocity  of  sound  varies  as  the  square  root  of  elas- 
ticity and  inversely  as  the  square  root  of  density.  A  wave- 
length is  the  distance  between  any  point  on  a  wave  and  a 
similar  point  on  the  wave  before  or  behind  it.  The  amplitude 
of  vibration  is  the  greatest  distance  traversed  by  a  particle  in 
either  direction  from  a  median  position;  that  is,  a  wave-height. 
Musical  notes  are  produced  by  repeated,  rapid,  regular  vibra- 
tions; noise  by  a  single  short  sound  or  a  confused  and  irregular 
mixture  of  sounds. 

Loudness,  or  intensity,  varies  inversely  as  the  square  of 
the  distance  and  directly  with  the  square  of  the  amplitude  of 
the  vibrations;  also  with  the  density  of  the  medium  and  at- 
mospheric motion.  It  is  increased  by  reflection  from  a  neigh- 
boring sonorous  body,  such  as  a  sounding-board,  or  from  the 
walls  of  a  room  (resonance),  and  is  maintained  for  long  dis- 
tances in  straight,  cylindric  tubes  (speaking-tubes).  Echoes 
are  the  result  of  reflection  forming  return-waves.  In  sound, 
as  in  other  forces,  the  angle  of  reflection  equals  the  angle  of 
incidence.  Sound  is  also  refracted  by  passing  through  media 
of  differing  densities. 


64  MEDICAL  PHYSICS. 

Pitch  depends  upon  the  number  of  vibrations  per  second. 
The  limit  of  perceptible  sounds  is  from  16  per  second  for  deep 
sounds,  to  40,000  per  second  for  high  sounds.  The  human 
voice  ranges  from  100  to  1000  vibrations  per  second.  Vibra- 
tion-frequency in  pipes  varies  inversely  as  the  length;  open 
pipes  are  twice  as  long  as  closed  pipes  of  the  same  pitch.  The 
vibration-frequency  of  strings  of  the  same  material  varies  in- 
versely as  the  length  and  the  square  root  of  the  weights,  and 
directly  as  the  square  root  of  the  tension.  The  siren  is  an  in- 
strument for  the  determination  of  vibration-frequency. 

Middle  C  has  256  or  264  vibrations  per  second.  Each 
octave  contains  double  the  number  of  vibrations  of  the  one 
just  below  it,  and  one-half  of  that  above.  If  the  ratio  of  in- 
tervals of  three  notes  is  4:5:6  they  form  a  harmonic  triad. 
If  to  these  three  a  fourth  note,  the  octave  of  the  first  one,  is 
added,  we  have  a  major  chord.  In  a  minor  chord  the  ratio  is 
10:12:15,  with  the  octave  of  the  first  note.  Quality,  or  timbre, 
varies  with  the  nature  of  sound-producing  bodies,  and  depends 
on  the  form  of  vibrations  due  to  the  combination  with  funda- 
mental tones  of  harmonics  or  overtones:  i.e.,  the  sounds  pro- 
duced by  the  vibration  of  an  instrument  in  parts. 

The  musical  scale  is  made  up  of  gamuts  or  series  of  notes 
connecting  octaves.  These  notes  are  represented  by  the  letters 
C,  D,  E,  F,  G,  A,  and  B.  If  the  vibrations  of  C  be  represented 
by  1,  those  of  D  are  9/8;  of  E,  5/4;  of  F,  */»;  G,  V2;  A,  5/3; 
B,  15/8;  and  the  octave  C,  2.  The  larger  intervals  (9/8  and 
10/o)  between  these  notes,  obtained  by  dividing  the  larger  frac- 
tions by  the  smaller,  are  termed  tones;  the  smaller  interval 
(16/15),  semitones. 

Interference  of  sounds  may  intensify  or  nullify  motion, 
according  as  the  hollow  of  one  wave  fits  in  the  hollow  or  the 
crest  of  another.  The  wavy  sounds  produced  by  interference 
are  called  beats;  the  number  per  second  from  two  simple  notes 
equals  the  difference  of  their  vibration-numbers.  Interference 
in  .cords  commonly  results  in  vibrations  in  loops  or  segments: 
the  points  of  least  vibration  are  called  nodes;  the  points  of 
greatest  motion,  antinodes.  Sympathetic  vibrations  are  those 
produced  in  a  body  by  the  vibrations  of  another  body  near  by. 
They  are  termed  forced  vibrations  when  the  body  acted  on 
was  already  in  vibration,  but  was  made  to  assume  the  vibra- 
tion-period of  the  other. 

The  ear,  or  organ  of  hearing,  is  designed  to  gather  and 
convey  sound-waves  by  vibrations  of  the  tympanum  and  the 
chain  of  bones  in  the  middle  ear,  to  the  vestibule  and  cochlea 
of  the  inner  ear.  The  organ  of  Corti  consists  of  about  3000 


SOUND.  65 

minute  bristles  of  various  lengths,  suspended  in  the  liquid 
here;  they  "take  up  and  analyze  the  vibrations,  much  as  when 
we  sing  into  a  piano  with  the  damper  down,  only  those  strings 
respond  which  are  in  unison  with  the  sound  produced  by  the 
voice."  These  bristles  are  connected  with  nerve-filaments, 
which  transmit  the  sensory  impressions  to  the  auditory  center 
of  the  brain. 

The  larynx,  or  voice-box,  is  "a  reed-instrument  situated 
at  the  top  of  the  windpipe,  or  trachea."  The  elastic  vocal 
chords  are  stretched  across  the  orifice:  laxly  when  breathing, 
more  tightly  during  vocal  action.  Tension  is  regulated  by 
muscular  action,  and,  the  tenser  the  cords,  the  higher  the 
pitch.  The  mouth  and  nasal  passages  serve  as  resonators,  and 
change  shape  in  accordance  with  vocalization  and  articulation. 
"Chest-notes"  are  produced  by  vibration  of  vocal  cords  as  a 
whole;  falsetto  notes  by  vibration  of  the  free  edges.  Two 
octaves  is  the  average  extent  of  scale  of  the  human  voice.  The 
wave-length  of  voice  in  women  during  ordinary  conversation  is 
2  to  4  feet;  in  men,  8  to  12  feet. 

The  tuning-fork  is  an  instrument  much  used  in  the  dif- 
ferential diagnosis  of  ear-troubles.  In  testing  bone-conduction 
it  is  placed  with  the  end  of  the  handle  resting  at  a  right  angle 
on  the  mastoid  or  vertex.  Air-conduction  is  normally  superior 
to  bone-conduction,  and  the  fork  held  before  the  meatus  should 
be  heard  twice  as  long  as  on  the  mastoid;  or  if  the  vibration 
ceases  to  be  audible  on  the  bone  it  should  still  be  heard  at  the 
orifice  of  the  auditory  canal.  When  the  fork  is  heard  longer 
by  bone-conduction,  the  canal  or  the  middle  ear  is  affected. 
In  labyrinthine  disease  the  impairment  of  hearing  is  the  same 
for  air-  and  for  bone-  conduction. 

The  phonograph  consists  essentially  of  a  metal  cylinder 
rotated  by  a  crank  and  covered  with  wax  or  tin-foil  and 
threaded  like  a  screw;  over  the  furrow  is  set  a  vibrator",'  style 
at  the  bottom  of  the  mouth-piece.  Every  movement  of  the  style 
caused  by  the  voice  is  thus  recorded  by  impressions  in  the  foil, 
and  if  the  cylinder  is  brought  back  to  its  original  position  and 
turned  as  before,  the  style  will  play  up  and  down  over  the 
depressions  and  ridges,  and  so  repeat  the  spoken  words. 

The  audiphone  is  a  fan-shaped  sheet  of  ebonite  or  elastic 
card-board  held  between  the  teeth  of  persons  partially  deaf, 
to  aid  them  in  hearing. 


66  MEDICAL  PHYSICS. 


QUESTIONS  ON  MEDICAL  PHYSICS. 

1.  Mention  a  form  of  matter  perceived  by  smell,  but  not  by 
sight;  one  recognized  by  feeling,  and  not  by  sight. 

2.  Distinguish  between  a  physic  and  a  chemic  change,  and  men- 
tion an  example  of  each. 

3.  Distinguish  between  volume,  mass,  and  density. 

4.  Name  the  three  chief  metric  units,  and  explain  their  mutual 
relations. 

5.  Read  the  following:  0.025  m.;  25.365  gm. 

6.  Write  as  one  number  1  kg.  and  1  mg. 

7.  How  many  grams  in  a  dram?     In  an  ounce? 

8.  What  is  the  length  in  English  measure  of  a  meter?     Of  a 
millimeter?    Of  a  micromillimeter? 

9.  What  is  the  capacity  in  English  measure  of  a  liter? 

10.  How  many  milligrams  in  a  kilogram? 

11.  Write  a  metric  prescription  for  a  2-ounce  mixture,  teaspoonful 
doses,  using  the  following  drugs  and  doses:    Potassium  acetate,  gr.  x; 
salicylic  acid,  gr.  xx;  water,  to  fill  the  bottle. 

12.  What  difference  between  a  Troy,  or  apothecary's,  ounce  and 
an  avoirdupois  ounce?    Same  as  to  pound? 

13.  Does  a  pint  of  water  weigh  a  pound? 

14.  What  difference,  if  any,  between  a  minim  and  a  drop? 

15.  How  many  grains  of  corrosive  sublimate  to  the  pint  of  water 
in  making  a  1  to  1000  solution? 

16.  A  4-per-cent.  solution  of  cocain  contains  how  many  grains  to 
the  ounce? 

17.  How  do  high  altitudes  mechanically  help  weak  lungs? 

18.  What  is  the  use  of  the  neck  of  a  pitcher? 

19.  If  a  body  is  of  the  same  sp.  gr.  as  water,  where  does  it  float? 

20.  Is   the   sp.  gr.   of   water   at   ordinary   temperature   below   or 
above  1? 

21.  What  effect  does  the  addition  of  water  to  alcohol  have  on 
the  sp.  gr.  of  the  latter? 

22.  A  piece  of  brass  weighs  37.71  gm.  in  air,  32.21  in  water.    Find 
its  sp.  gr. 

23.  A  piece  of  metal  weighs  40  gm.  in  air,  and  displaces  a  trifle 
more  than  2  c.c.  of  water.    What  is  the  approximate  sp.  gr.  of  the  body, 
and  of  what  metal  is  it  composed?     (See  table.) 

24.  The  sp.  gr.  of  caustic  potash  is  2.1.    About  what  is  the  sp.  gr. 
of  a  10-per-cent.  solution  in  water? 

25.  W7hat  is  the  approximate  strength  of  a  solution  of  dilute  sul- 
phuric acid  (sp.  gr.,  1.40)  ? 

26.  Why  are  gases  more  compressible  than  liquids  or  solids? 

27.  What  is  the  sp.  gr.  of  a  lump  of  sugar  weighing  20  gm.  in  air 
and  9  gm.  in  oil  of  turpentine  (sp.  gr.,  0.865)  ? 

28.  Why  is  water  stale  after  boiling? 

29.  Why  is  it  difficult  to  push  an  inverted  tumbler  directly  down- 
ward into  a  vessel  of  water? 

30.  Why  does  a  string  attached  to  and  capable  of  holding  up  a 
weight  break   suddenly  when  jerked?      (Fractures   of  the  patella   and 
other  bones  have  been  caused  by  muscular  action.) 

31.  Why  do  bubbles  appear  on  a  glass  plate  immersed  in  water? 

32.  Why  does  quicksilver  not  wet  the  fingers? 

33.  Give  an  example  of  each  of  the  four  kinds  of  elasticity. 

34.  Why  are  cables  stronger  than  chains  of  the  same  size? 


QUESTIONS.  67 

35.  What  difference  in  weighing  with  scales  at  sea-level  and  at 
high  altitudes? 

36.  What   is   the   volume   of   a    liter   of   hydrogen    (at   ordinary 
pressure)   when  subjected  to  a  pressure  of  100  atmospheres? 

37.  Twelve  liters  of  oxygen  at  standard  temperature  and  pressure 
undergo   what   change   in  volume   at   a   temperature   of   60°   C.   and  a 
pressure  one-fourth  less?      (12.000  X  333/273  X  700/B70.) 

38.  Oxygen  is    16   times  as  dense   as  hydrogen.     What  is  their 
diffusion-ratio  ? 

39.  Explain  nose-bleed  on  ascending  high  mountains. 

40.  Explain  the  weather-changes  of  the  barometer. 

41.  What  is  the  siphonage-force  in  grams  of  a  siphon  2  cm.  in 
caliber,  the  long-arm  sine  being  40  cm.  and  the  sine  of  the  short  arm 
15  cm.? 

42.  How  does  charcoal  act  as  a  deodorizer? 

43.  Why  is  it  easier  to  descend  the  stairs  than  to  ascend  them? 

44.  Define  and  give  an  illustration  of  the  principle  of  the  correla- 
tion and  conservation  of  energy. 

45.  Explain  the  relationships  of  heat,  light,  and  electricity. 

46.  Why  do  people  in  warm  countries  wear  light-colored  clothing? 

47.  Why  do  muddy  roads  dry  more  quickly  in  windy  weather? 

48.  What  time  of  day,  as  a  rule,  is  the  relative  humidity  of  the 
atmosphere  greatest? 

49.  Why  does  the  wind  often  go  down  with  the  sun? 

50.  Why  is  it  more  often  cloudy  morning  and  evening  than  in  the 
middle  of  the  day? 

51.  Contrast  the  direction  of  the  air-currents  at  the  top  and  the 
bottom  of  an  outside  door  in  winter  and  in  summer. 

52.  Why  is  frost  more  likely  to  be  seen  after  a  clear  than  a 
cloudy  night? 

53.  Why  is  mercury  preferred  to  water  for  thermometers  and 
barometers? 

54.  State  the  normal  temperature  of  the  human  body    (mouth) 
in  F.  and  in  C.  readings. 

55.  Change  —  40°  F.  to  the  centigrade  scale. 

56.  Why  are  the  rails  on  a  railway  not  joined  together  more 
closely?     The  height  of  Eiffel's  tower  (989  feet)  varies  8  inches  during 
the  year. 

57.  The  altitude   of  Denver  is   exactly  one  mile.     What   is   the 
b.p.  (centigrade)  of  water  here? 

58.  Which  has  the  higher  b.p.,  fresh  water  or  sea-water? 

59.  Which  warms  more  quickly,  ice  or  water? 

60.  Why  is  damp  cold  more  chilling  than  dry  cold? 

61.  How  distinguish  between  a  physic  and  a  chemic  solution? 

62.  Name  a  solid  substance  which  aids  in  the  solution  of  another. 

63.  Why  is  sterilization  of  surgical  supplies  more  effective  with 
steam  heat  than  with  dry  heat? 

64.  If  we  mix  a  pound  of  water  at  80°  with  another  pound  at  0°, 
what  is  the  temperature  of  the  mixture?     Suppose,  in  the  second  case, 
we  use  a  pound  of  snow  or  ice,  what  then? 

65.  How  many  pounds  of  water  would  a  pound  of  steam  (at  100°) 
raise  from  the  f.p.  to  the  b.p.? 

66.  Which  would  be  more  affected  by  sudden  thermal  changes, 
a  roughly-finished  or  a  highly-polished  dental  filling? 

67.  What  causes  borax  and  many  other  salts  to  swell  upon  heat- 
ing? 


68  MEDICAL  PHYSICS. 

68.  What  is  the  temperature  of  water  at  the  bottom  of  a  pond 
in  winter? 

69.  Where  is  the  warmest  air  in  a  room,  and  why? 

70.  Is  the  heat  of  the  body  mostly  mechanic  or  chemic  in  origin? 

71.  Why  are  the  nights  comparatively  cooler  in  dry,  high  climates? 

72.  Why  do  thick  glass  vessels  break  when  suddenly  heated  or 
cooled? 

73.  Why  not  use  alcohol  for  cleansing  varnished  surfaces? 

74.  Distinguish  between  deliquescence  and  efflorescence. 

75.  Explain  steam-heating. 

76.  What  liquid  boils  at  about  temperature  of  the  body? 

77.  Why  does  early  frost  appear  on   some   objects   and  not   on 
others? 

78.  What  causes  "sweating"  of  ice-water  pitchers? 

79.  Explain  principle  of  glass  hot-beds. 

80.  How  does  vinegar-  or  alcohol-  sponging  cool  our  bodies? 

81.  Why  is  our  breath  visible  in  winter? 

82.  Why  is  it  nearly  always  cooler  when  the  wind  blows? 

83.  How  is  the  straight  rising  of  smoke  a  sign  of  fair  weather? 

84.  Is  more  heat  used  up  in  melting  ice  or  in  boiling  water? 

85.  Name  the  three  forms  of  radiant  energy. 

86.  Why  cannot  one  see  around  a  corner? 

87.  Explain,   with   diagrams,   how    a    too    great    antero-posterior 
diameter  of  the  eyes  causes  far-sight,  and  a  too  long  diameter  near- 
sight.     (Rays  of  light  are  refracted  by  the  crystalline  lens,  crossing  each 
other  a  little  behind  the  lens,  so  that  the  retinal  image  is  an  inverted 
one.) 

88.  How  does  polarized  light  differ  from  ordinary  light? 

89.  What  is  the  wavy  motion  seen  around  stoves  in  winter? 

90.  Why  does  a  street  appear  to  grow  narrower  farther  away? 

91.  Why  does  the  rising  sun  or  moon  look  larger? 

92.  Name  and  explain  the  three  kinds  of  spectra. 

93.  Why  do  electric  cars  run  better  in  fair  than  in  stormy  weather? 

94.  Name  and  define  the  three  chief  units  of  current  electricity. 

95.  Compare  the  electric  resistance  of  the  skin  with  that  of  the 
Atlantic  cables. 

96.  Which  electrode  has  a  drying  action,  and  which  a  softening 
effect,  and  why? 

97.  What  causes  the  compass  to  point  north  and  south? 

98.  Mention  the  chief  differences  between  the  galvanic  and  the 
faradic  current. 

99.  Why   does   the   faradic   hand-cathode   feel    stronger   than   the 
anode  ? 

100.  Why  does  acidulated  water  break  up  more  easily  by  electrol- 
ysis than  pure  water  does? 

101.  Distinguish  between  osmosis  and  dialysis. 

102.  Why   do    sodium   chlorid   solutions    exert    a    greater    osmotic 
pressure  than  an  equivalent  strength  of  a  sugar  solution? 

103.  What  are  isotonic,  hypertonic,  and  hypotonic  solutions? 

104.  Name  the  six  systems  of  crystals,  and  mention  an  example 
under  each. 

105.  To  what  is  the  color  of  most  crystals  due? 

106.  Why  are  sounds  less  intense  on  a  mountain  than  in  a  valley? 

107.  How  does  a  common  cold  change  the  voice? 

108.  If   a   flash   of   lightning   is   followed   in   five   seconds    by    the 
thunder,  what  is  the  distance? 


QUESTIONS.  69 

109.  What  are  the  three  principal  properties  of  sound,  and  on  what 
eHo1^?does  stoppage  of  the  Eustachian  tube  cause  partial 
temp TnyHdoewndeisStinguish  between  deafness  due  to  external-,  to  mid- 
dle''  nlW™1: dSSn?SSL  heard  better  at  night,  and  also  often 
before  a^  storm  ?^  ear_trmnpetSj  stethoscopes,  and  megaphones  aid  hear- 
ing! 


CHEMIC  PHILOSOPHY. 


ELEMENTS. 

AN  element  is  a  substance  composed  of  only  one  kind  of 
matter.  Iron,  gold,  hydrogen,  and  oxygen  are  elements. 
Chemic  compounds  are  made  up  of  more  than  one  kind  of 
matter.  Water  is  a  compound  substance,  since  it  can  be  de- 
composed by  electrolysis  into  hydrogen  and  oxygen.  There 
are  about  80  elements  known  at  the  present  time,  12  of  which 
at  ordinary  temperatures  are  gases,  2  liquids,  and  the  remainder 
solids.  By  far  the  greater  number  are  metals;  the  non-metallic 
elements  are  often  termed  metalloids.  The  names  of  the  ele- 
ments are  generally  Latin  (end  in  urn],  and  indicate  some 
peculiar  or  fancied  property.  Some  of  the  well-known  ele- 
ments have  both  an  English  and  a  Latin  name;  most  of  these 
were  known  to  the  ancients. 

The  symbol,  or  sign,  of  an  element  is  made  up  of  the 
initial  and  sometimes  another  distinctive  letter  from  the  Latin 
name:  e.g.,  C  for  carbon,  Ca  for  calcium,  Cl  for  chlorin,  Cu 
for  copper  (Latin,  cuprum),  etc. 

TABLE  OF  ELEMENTS. 


NAME. 

SYMBOL. 

VALENCK. 

ATOMIC 
WEIGHT. 

USUAL 
POLARITY. 

Aluminum  ...           ... 

Al 

TV    I  A  I     _  VT\ 

97  04 

Antimony            ....           .    . 

Sb 

m-y 

I  10   R 

Argentum  (see  "Silver  "). 
Argon       .    -    . 

A" 

-in  7 

Arsenic                        .    .    . 

As 

mv 

74  Q 

Aurum  (see  "Gold"). 
Barium     

Ba 

jj 

lQf{  q 

Be 

H 

Q  AQ 

Bi 

mv 

OAQ  q 

I 

Boron 

B 

III 

10  Q 

T 

Br 

I    III    V    VII 

7q  7fj 

Cadmium     ...       

Cd 

II 

]11  5 

_L 

Calcium   

Ca 

II 

39  91 

I  , 

c 

IT    IV 

nQ7 

1 

Cerium     ... 

Ce 

II  IV  (  Ce  —  vi  ^ 

-|Qq  q 

Cesium     

Cs 

I 

132  7 

1 

Chlorin     

Cl 

I,  III    V    VII 

35  37 

1 

Chromium  .    . 

Cr 

IT   iv  (Cr  —  vi  ) 

ro  n 

Cobalt  

Co 

II    IV  (  Co,  —  VI  ) 

58  6 

1 

Columbium     

Cb 

v 

93  7 

r 

Cu 

ii  (Cu  —  ii  ) 

fJQ    10 

Cm 

(70) 


ELEMENTS. 


71 


TABLE  OF  ELEMENTS  (Continued). 


NAME. 

SYMBOL. 

VALENCE. 

ATOMIC 
WEIGHT. 

USUAL 
POLARITY. 

Er 

II  (Er,  —  VI  ) 

166  0 

_[- 

Ferrum  (see  "Iron"). 

F 

I 

19.0 

Gd 

156.1 

-f 

Ga 

III 

69.9 

4- 

Germanium     
Glucinum  (see  "Beryllium"), 
(jjold                     

Ge 
Au 

II,  IV 

I,  III 

72.3 

196.7 

+ 
4- 

Helium                

He 

Hydrargyrum  (see  "Mercury  "). 

H 

I 

1.0 

4. 

In 

II  (Il)2  =  VI  ) 

113.6 

-f 

I 

I,  III,  V,  VII 

126.53 

Ir 

II,  IV,  VI 

192.5 

4. 

Iron       ...        
Kalium  (see  "  Potassium  "). 

Fe 
Kr 

ii,  iv  (Fe2  —  vi  ) 

55.88 
80.0 

+ 

La 

in 

138.2 

-h 

Lead          

Pb 

II,  IV 

206.4 

Li 

i 

7.01 

-f 

Me 

ii 

24.3 

4- 

Mn 

£i,  iv(Mn2  =  vi) 

54.8 

+ 

Ms 

228.0 

Mercury  

Hg 

(Hg,  =ll),  ii 

199.8 

-f 

40.0 

Molybdenum  .    
Natrium  (see  "Sodium"). 
Neodymium 

Mo 
Nd 

II,  IV,  VI 

ii 

95.9 
140.5 

4- 

Neon                         .    .    . 

Ne 

22.0 

Nickel      .    .               
Niobium  (see  "Columbium  "). 
Nitrogen 

Ni 

N 

ii,  iv  (Ni2  =  vi) 
I    III    V 

58.6 
14.01 

+ 

Osmium    

Os 

II,  IV,  VI,  VIII 

190.3 

4- 

Oxygen     

o 

II 

15.96 

Palladium    
Phosphorus      .        .        ... 

Pd 
p 

II,  IV 
III,  V 

106.35 
30.96 

+ 

Platinum      .    . 

Pt 

II,  IV 

194.3 

4- 

Plumbum  (see  "Lead"). 

K 

I 

39.03 

4- 

Praseodymium    

Pr 

II 

143.5 

4- 

Rhodium                      .... 

Rh 

II,  IV 

102.9 

4- 

Rubidium            

Rb 

I 

85.2 

-j- 

Ruthenium  

Ru 

II,  IV,  VI,  VIII 

101.4 

+ 

Samarium        •    .        .    .            . 

Sm 

III    V 

149.6 

4- 

So 

III 

43.9 

+ 

Se 

II,  IV,  VI 

78.9 

Si 

II,  IV 

28.3 



Silver    

Ag 

I 

107.66 

4- 

Sodium     
Stannum  (see  "Tin"). 

Na 

I 

23.0 

+ 

CHEMIC  PHILOSOPHY. 
TABLE  OF  ELEMENTS  (Concluded). 


NAME. 

SYMBOL. 

VALENCE. 

ATOMIC 
WEIGHT. 

USUAL 
POLARITY. 

Stibium  (see  "Antimony"). 
Strontium    

Sr 

II    IV 

87  3 

4. 

Sulphur        .    . 

S 

II    IV    VI 

31  98 

Tantalum     

Ta 

III    V 

182  0 

Tellurium    

Te 

II,  IV,  VI 

125  0 

Terbium                       

Tb 

III 

159  1 

4. 

Thallium             

Tl 

I    III 

203  7 

4- 

Th 

IV 

231  9 

+ 

Thulium  

Tu 

170  7 

-j- 

Tin    

Sn 

II,  IV 

118.8 

4- 

Titanium      ,       .           

Ti 

II    IV 

48  0 

Tungsten      

W 

II    IV    VI 

183  6 

Uranium  

u 

ii,  iv  (Uo  —  vi  ) 

238.8 

4- 

Vanadium    
Wolfram  (  see  "  Tungsten  "  )  . 
Ytterbium        . 

V 
Yb 

III,  V 
III 

51.1 

172  6 

4. 

Yttrium    .... 

Yt 

III 

88  9 

4. 

Zinc  .        •    .            

Zn 

II 

65  1 

4- 

Zirconium    
Xenon,  Polonium,  Radium,  etc. 

Zr 

II,  IV 

90.4 

+ 

ATOMS  AND  THEIR  PROPERTIES. 

An  atom  is  the  smallest  indivisible  particle  of  matter  that 
can  take  part  in  a  chemic  change.  Atoms  do  not  usually  exist 
separately,  but  are  held  together  by  chemism,  or  chemic  affinity 
(polarity),  so  as  to  form  molecules.  A  molecule  may  therefore 
be  denned  as  the  smallest  portion  of  matter  that  can  exist  in 
a  free  state.  When  the  constituent  atoms  of  molecules  are 
alike,  we  have  a  simple,  or  elemental,  molecule;  when  the 
atoms  are  unlike,  a  compound  molecule.  Simple  molecules 
make  up  elements;  compound  molecules,  compound  substances. 

An  element  in  the  free,  nascent,  unsaturated,  or  atomic 
state  has  a  more  powerful  action  on  other  substances  than 
when  in  combination,  since  no  force  is  spent  in  breaking  up 
existing  molecules.  Free  atoms  have  no  polarity  until  they 
enter  into  combination. 

Labile  chemic  compounds  are  unstable  bodies,  and  readily 
undergo  chemic  change:  either  a  disruption  of  the  molecule 
or  a  new  intramolecular  arrangement  of  atoms,  which  tend  to 
migrate  to  a  more  stable  position.  The  term  stabile  indicates 
the  reverse  of  labile.  Potential,  or  static,  labile  compounds 
include  the  explosives,  such  as  nitroglycerin.  Chemic  changes 


ATOMS.  73 

destroy  static  labile  compounds,  whereas  dynamic,  or  kinetic, 
labile  compounds  pass  into  polymeric  or  isomeric  compounds: 
i.e.,  the  atoms  take  on  a  different  arrangement  within  the 
molecule,  or  several  like  molecules  are  fused  together  into  one. 


ATOMICITY. 

It  has  been  determined  by  careful  experiments  that  most 
elemental  molecules  are  diatomic:  i.e.,  they  contain  two  atoms. 
Ilg,  Cd,  Zn,  and  Ba  are  monatomic;  Se  and  0  (ozone),  tri- 
atomic;  As  and  P,  tetratomic;  S  (below  550°),  hexatomic. 
Colloid  molecules  have  more  atoms  than  crystalloid;  hence  are 
larger.  The  physic  properties  of  substances  vary  greatly  ac- 
cording to  the  method  of  atomic  linking,  which  in  true  chemic 
compounds  is  always  an  unbroken  system.  The  different  forms 
and  properties  which  some  elements  assume  according  to  the 
ways  in  which  their  constituent  atoms  face  each  other  in  the 
molecule,  is  termed  allotropic.  In  chemic  nomenclature  the 
symbol  of  an  element  represents  also  one  atom  of  the  element. 

Experiment. — If  equal  volumes  of  the  two  gases  H  and  Cl  are 
brought  together  in  a  glass  vessel  in  the  light,  they  quickly  combine, 
forming  hydrochloric  acid  gas,  and  the  green  color  of  the  Cl  is  entirely 
lost.  Now,  according  to  Avogadro's  law,  each  elemental  gas  contained 
the  same  number  of  elemental  molecules;  say,  a  billion.  But  the  com- 
pound gas  occupies  the  same  space  as  both;  hence  it  contains  2,000,000,- 
000  molecules,  each  of  which  is  made  up  of  1  atom  of  H  and  1  atom  of 
Cl.  To  furnish  1  atom  to  each  compound  molecule  every  simple  mole- 
cule of  H  and  of  Cl  must  therefore  consist  of  2  atoms.  In  much  the 
same  way,  by  electric  synthesis  or  analysis,  it  is  readily  proved  that 
the  molecule  of  water  contains  2  atoms  of  H  and  1  of  O;  and  so  on 
with  other  elements  and  compounds. 


ATOMIC  WEIGHTS. 

The  actual  weight  of  the  atom  of  any  element  is,  of  course, 
an  imponderable  quantity,  but  the  relative  weights  of  ele- 
mental atoms  is  easily  determined  by  comparing  the  weights 
of  equal  volumes  of  these  elemental  substances  in  the  gaseous 
state  and  at  the  same  temperature  and  pressure,  making  due 
allowance  for  atomicity.  The  atomic  weight  of  any  element 
is  the  weight  of  an  atom  of  the  element  as  compared  with  the 
weight  of  an  atom  of  H,  taken  as  the  unit,  or  1.  The  atomic 
weight,  for  instance,  of  0  is  approximately  16;  of  Br,  80;  of 
Na,  23.  The  density,  or  relative  mass,  of  an  element  is  equiv- 
alent to  the  atomic  weight,  providing  both  elements  compared 
have  the  same  number  of  atoms  to  each  molecule.  For  exam- 


74  CHEMIC  PHILOSOPHY. 

pie,  0  and  H  both  contain  2  atoms  in  the  elemental  molecule; 
hence  the  density  of  0  is  16.  Hg,  on  the  other  hand,  has  an 
atomic  weight  of  nearly  200,  and  contains  only  1  atom  to  the 
molecule;  its  density  is,  therefore,  one-half  of  200,  or  100. 
Briefly  stated,  the  density  is  half  the  molecular  weight,  by 
which  is  meant  the  sum  of  the  weights  of  all  the  atoms  in  a 
molecule. 

It  is  necessary  to  know  the  atomic  weights  of  the  different 
elements  in  making  most  chemic  calculations.  For  most  ordi- 
nary purposes  fractions  are  disregarded  and  the  nearest  whole 
numbers  employed.  Atomic  weights  are  inversely  proportional 
to  the  specific  heats  of  elements,  or,  in  other  words,  the  atoms 
of  the  various  elements  have  equal  capacities  for  heat.  The 
product  of  the  specific  heat  of  any  element  by  its  atomic  weight 
gives  a  nearly  constant  quantity:  namely,  6.4.  Elements  of 
the  same  class  vary  in  potency  directly  with  their  atomic 
weights;  hence  it  is  a  law  that  "the  properties  of  an  element 
are  a  periodic  function  of  its  atomic  weight/7 


POLARITY. 

As  already  stated  in  the  section  on  physics,  when  an  elec- 
trolyte is  decomposed  by  electrolysis,  the  metal  or  -f-  element 
(cation)  clings  to  the  —  pole,  while  the  —  element  or  part 
(anion)  is  set  free  at  the  +  pole.  Metals  are,  therefore,  elec- 
tropositive in  nature;  metalloids,  electronegative.  Yet  this 
classification  is  relative  and  a  question  of  degree:  some  metals 
are  more  positive  than  others;  some  metalloids  more  negative 
than  other  non-metals.  0  is  the  most  —  of  elements;  Cs,  the 
most  -}-. 

The  following  short  list,  comprising  the  more  common 
elements,  represents  this  relationship,  each  element  being  + 
to  the  ones  which  precede  and  —  to  those  that  follow:  0,  S, 
1ST,  Cl,  Br,  I,  P,  As,  B,  C,  Sb,  Si,  H,  Au,  Pt,  Hg,  Ag,  Cu,  Bi, 
Sn,  Pb,  Co,  Ni,  Fe,  Mn,  Ce,  Al,  Mg,  Ca,  Sr,  Ba,  Li,  Na,  K,  Cs. 

In  chemic  compounds  plus  and  minus  elements  are  com- 
bined, and,  the  wider  the  difference  in  their  polarity,  the 
greater  the  attraction  between  them,  and,  generally  speaking, 
the  stronger  the  combination. 

Experiment. — Cut  a  piece  of  the  metal  K,  and  note  how  quickly 
the  cut  surface  whitens  (oxidizes). 

When  two  elements  of  the  same  family  are  capable  of 
combining  directly  with  each  other,  the  one  having  the  highest 
atomic  weight  takes  the  positive  role.  H  and  B  invariably 


VALENCE.  75 

take  the  positive  role  in  combining  with  other  elements,  as  do 
most  metals.  0  and  P  are  always  negative  in  their  compounds. 
Atoms  of  C,  N",  and  P  may  have  both  +  and  —  bonds  con- 
currently. The  polarity  of  the  atoms  in  an  elemental  molecule 
must  be  the  converse  of  each  other:  that  is,  +  an(^  —  (divided 
polarity).  When  such  a  molecule  enters  into  a  chemic  change, 
both  atoms  become  of  like  polarity:  that  is,  -j-  or  — .  H  has 
a  reducing-power  of  2  units,  because  in  combining  with  other 
elements  its  negative  atom  rises  in  polarity  from  —  1  to  -|-  1: 
an  algebraic  difference  of  2.  In  combinations  of  C,  H,  and  0 
the  C  bonds  united  to  H  are  negative;  those  joined  with  0 
are  positive. 


VALENCE. 

This  is  a  very  important  subject,  without  which  chemic 
nomenclature  can  never  be  really  understood.  Valence  (equiv- 
alence, quantivalence)  signifies  the  combining  or  replacing 
power  of  an  element  as  compared  with  H  taken  as  the  unit. 
Those  elements  which  combine  with  or  replace  H  atom  for 
atom  are  called  monads.  Such  as  require  2  atoms  of  H  to 
satisfy,  or  saturate,  or  neutralize  the  polarity  of  1  atom  of  the 
given  element  are  termed  diads.  The  triad  atom  replaces  or 
combines  with  3  of  H  or  any  other  monad;  the  tetrad,  4  (or 
2  diads);  the  pentad,  5;  the  hexad,  6;  the  heptad,  7;  the 
octad,  8.  The  Latin  adjectives  corresponding  with  these 
Greek  substantives  are  univalent,  bivalent,  trivalent,  quad- 
rivalent, quinquivalent,  sexivalent,  septivalent,  and  octivalent. 
Artiads  are  elements  with  an  even  valence;  perissads,  uneven. 
Monogenic  is  a  term  sometimes  applied  to  monads;  polygenic, 
to  all  other  elements.  The  law  of  even  numbers  is  that  in  all 
saturated  molecules  the  sum  of  the  perissad  atoms  is  always 
even,  and  molecules  composed  of  perissad  elements  contain  an 
even  number  of  atoms.  A  diad  element,  or  radical,  can  be  intro- 
duced into  a  compound  without  altering  the  valencies  of  other 
elements:  e.g.,  K  —  0  —  KandK  —  0  —  0  —  0  —  0  —  K. 

It  will  be  noticed  that  a  good  many  elements  have  more 
than  one  valence,  the  series  differing  by  2,  as  a  rule.  The 
higher  valence  is  shown  only  when  the  element  is  acting  the 
+  role  in  connection  with  0,  which,  on  account  of  ultra- 
negativity,  seems  to  draw  out  the  full  polarity  of  the  more 
positive  element  with  which  it  is  combined. 

The  following  table  shows  at  a  glance  the  usual  valence  of 
each  of  the  more  common  elements: — 


76 


CHEMIC  PHILOSOPHY. 


MONADS. 

DlADS. 

TBIADS. 

TETRADS. 

PENTADS. 

HEXADS. 

HEPTADS. 

OCTADS. 

F 

0 

Cl 

S 

Cl 

S 

N 

Os 

Cl 

s 

N 

c 

N 

Cr 

Cl 

Ru 

Br 

Hg  (ic) 

P 

Si 

P 

Mn 

I 

Cu  (ic) 

As 

Pt 

As 

H 

Pb 

B 

Su  (ic) 

Ag 

Cd 

Sb 

Li 

Co 

Au 

Na 

Ni 

Bi 

K 

Fe  (ous) 

Cr  (mis) 

Mn  (ous) 

Zn 

Mg 

Ca 

Sr 

TD^. 

r>a 

Sn  (ous) 

The  valence  of  an  element  can  be  indicated  in  one  of 
three  ways:  1.  By  Eoman  numerals  placed  above  the  symbol 
and  to  the  right;  as,  H1,  On,  Nm,  CIV.  2.  By  single  dashes 
representing  double  (positive  and  negative)  bonds  of  union,  or 
points  of  attraction,  or  poles  of  the  atomic  magnet;  as,  H  — , 
—  0  — ,  N^^,  =  C  =.  3.  By  accent-marks  written  to  the 
right  and  above  the  symbol;  as,  Cl'. 

Exercise. — Practice  on  combining  the  positive  with  the  negative 
elements  of  the  table  above,  according  to  their  valence,  writing  the 
positive  element's  symbol  first.  For  example:  NaCl,  PbI2,  AuCl3,  SO2, 

PA. 

The  true  combining  value,  or  polarity  value,  of  any  atom 
in  combination  is  the  algebraic  sum  of  its  +  and  -  -  bonds. 
An  atom  having  3  negative  bonds,  and  another  having  3  posi- 
tive bonds,  are  of  equal  valence,  but  the  difference  in  their 
respective  polarity-value  is  6.  Thus,  KMn04  has  an  oxidizing- 
power  of  5  units,  since  the  difference  in  polarity  between  Mn 
in  this  compound  and  Mn  in  the  reduced  (deoxidized)  man- 
ganese compound  is  7  —  2,  or  5.  The  lowest  possible  polarity- 
value  is  — 4;  the  highest  polarity-value,  -j-  8;  but  the  differ- 
ence between  the  highest  and  the  lowest  polarity-value  in  the 
same  atom  never  exceeds  8  units.  The  algebraic  sum  of  the 
-j-  and  —  bonds  holding  any  two  or  more  atoms  together  is 
zero.  Any  increase  or  diminution  in  the  polarity-value  of  any 
atom  or  group  is  always  accompanied  by  an  equal  converse 
diminution  or  increase  in  the  combining  atom  or  group.  In- 


MOLECULES.  77 

crease  of  polarity-value  is  termed  oxidation;  decrease  of  polar- 
ity-value, reduction.  Oxidizing  agents  are  atoms  or  groups 
that  will  sustain  a  diminution  of  polarity-value;  reducing 
agents  are  atoms  or  groups  that  can  gain  in  polarity-value. 
Free,  or  nascent,  0  is  an  oxidizing  agent,  because  when  it  enters 
into  combination  with  other  elements  it  acquires  2  negative 
bonds.  Free,  atomic  H  is  a  reducing  agent  for  the  converse 
reason. 


MOLECULES  AND  FORMULAS. 

The  molecule  has  already  been  defined  as  the  smallest 
portion  of  matter  that  can  exist  in  a  free  state,  or  independ- 
ently. Homogeneous  masses  are  made  up  of  like  molecules. 
When  the  atoms  composing  a  molecule  are  alike,  the  molecule 
is  simple,  or  elemental;  when  the  atoms  are  unlike,  they  form 
a  compound  molecule. 

A  radical  is  an  atom  or  a  group  of  atoms  common  to  a 
number  of  compounds.  A  single  atom  constitutes  a  simple 
radical;  a  group  of  unsaturated  atoms,  a  compound  radical. 
For  example,  the  Na  atom  is  a  simple  radical,  characteristic  of 
all  sodium  compounds;  HO  is  a  compound  radical  present  in 
every  hydrate.  Compound  radicals  may  be  regarded  as  residues 
left  on  removing  one  or  more  atoms  from  a  saturated  mole- 
cule; thus,  HO,  hydrate,  is  derived  from  H20  by  dropping  one 
atom  of  H.  The  valence  of  most  compound  radicals  is  easily 
determined  by  subtracting  the  sum  of  positive  polarities  from 
the  sum  of  the  negative  polarities,  or  vice  versa.  Fe,  Mn,  Or, 
and  Al  in  ic  compounds,  and  Cu  and  Hg  in  ous  compounds, 
unite,  each  element  with  itself  by  one  bond  of  union,  forming 
pairs  with  reduced  total  valence. 

A  formula  is  a  combination  of  symbols  representing  a 
molecule,  as  NaCl.  which  stands  for  a  molecule  of  sodium 
chlorid,  made  up  of  an  atom  each  of  Na  and  Cl.  H20  is  the 
formula  of  hydrogen  oxid,  or  water,  which  is  composed  of  2 
parts  of  H  and  1  of  0.  In  writing  formulas  we  place  the  -|- 
element,  or  radical,  always  first,  the  —  element,  or  radical,  fol- 
lowing, taking  care  that  the  valence  of  each  is  satisfied.  The 
multiplication  of  atoms  is  shown  by  small  figures  written  to  the 
right  and  below  the  symbol,  as  in  H20  or  HgCl2.  Compound 
radicals  taken  a  number  of  times  are  inclosed  in  parentheses; 
thus:  (NH4)2S04. 

The  following  table  of  compound  radicals  and  their  va- 
lences should  be  learned  by  heart: — 


78 


CHEMIC  PHILOSOPHY. 


PPPPPPPP22QQQQ 


ppbpp pP  ||   ||   ||   ||   II   (i  ||  $  II  I-  ||  |j 

n  .  MM."  "     (f   _          Ji,  tr1    II 


1 1.  8 

^1^1    2-^^pS    o'  ? 

"l*fffl}il 

E^     ^ 


IS    g: 

r  f 


<?  ii  li  1| 

E   P  a  ii 

li  |  si 

1 1  If 

«<  0* 

§ 
i 


FORMULAS.  79 

Exercise. — Practice  in  notation  of  formulas  with  the  aid  of  the  two 
preceding  tables.  For  example,  H2SO4,  Na2B4O7,  Fe2Cle. 

A  graphic,  structural,  or  rational  formula  differs  from  the 
ordinary  empiric  formula  in  that  the  arrangement  and  relation 
of  atoms  to  each  other  in  a  molecule  are  shown  pictorially.  In 
other  words,  not  only  the  composition,  but  the  constitution,  as 
well,  of  the  compound  is  shown.  Graphic  formulas  are  of  great 
interest  and  importance  in  organic  chemistry.  The  following 
are  examples: — 

H      O      AT  Na-0\ 

H  — O  — H  for  H20  ;  *       Q~N  forHNO2  5  Na  — O— p  for 


Fe 

F'e 


—  Cl 

—  Cl 

—  Cl 

for  Fe,Cl6 
-Cl 
-Cl 

—  Cl 


The  nomenclature  of  chemic  compounds  is  simpler  and 
more  definite  than  it  formerly  was.  Binary  compounds  (those 
containing  but  two  elements  directly  united,  or  a  positive  com- 
pound radical  and  a  negative  element)  are  read  by  naming  with 
its  proper  name  the  positive  element  or  radical,  and  then  the 
negative  element  with  its  ending  changed  to  id  (or  ide):  e.g.) 
NaBr,  sodium  bromid;  KI,  potassium  iodid,  etc. 

Exercise. — Write  formulas  and  name  ten  binary  compounds. 

Ternary  compounds  (those  containing  more  than  two  elements, 
indirectly  united,  or  more  than  a  —  element  and  a  +  radical)  are  named 
according  to  the  table  of  radicals  given  above.  It  will  be  seen,  as  per 
the  following  graphic  formulas,  that  the  ending  ate  indicates  a  higher 
valence  of  the  negative  element  than  does  ite,  and  still  higher  in  per — 
ate,  while  its  lowest  valence  is  expressed  by  hypo — ite. 

Potassium  hypochlorite       Potassium  chlorite  Potassium  chlorate  Potassium  perchlorate 

K  — O  — Cl1       K  —  O  —  r»im    K  —  O—  /^1  v    K  —  O—  y^M  vn 


c 


Exercise. — Write  formulas  and  name  ten  ternary  compounds. 

The  +  as  well  as  the  —  elements  sometimes  differ  in 
valence  in  different  compounds.  The  higher  valence  is  dis- 
tinguished by  changing  the  end  of  the  name  of  the  positive 
element  to  tc;  the  termination  ous  is  characteristic  of  the  lower 
valence.  Examples  are  Hg2Cl2,  mercurous  chlorid;  HgCl2, 
mercuric  chlorid;  Cu2Br2,  cuprous  bromid;  CuBr2,  cupric 
bromid;  FeCl2,  ferrous  chlorid;  and  Fe2Cl6,  ferric  chlorid. 


80  CHEMIC  PHILOSOPHY. 

The  formulas  of  acid  substances  are  readily  formed  by 
prefixing  the  requisite  number  of  H  atoms  to  the  corresponding 
radical:  to  the  monad  radical  1  H;  to  the  diad,  2,  etc.  Thus, 
the  radical  for  nitrite  is  X02,  the  formula  for  nitrous  acid 
HN02;  the  radical  for  nitrate  is  NO.,,  the  formula  for  nitric 
acid  is  HN03.  Again,  S04  is  the  diad  radical  for  sulphate,  and 
H2S04  the  formula  for  sulphuric  acid. 

Exercise. — Write  and  name  all  the  acid  formulas  that  can  be 
formed  from  the  radicals  ending  in  ate  or  ite  in  the  table  above. 

There  are  some  irregularities  in  chemic  nomenclature  aris- 
ing from  the  old  system  and  occasionally  met  with  in  medical 
literature.  The  most  important  of  these  anachronisms  are  the 
use  of  the  prefixes  per  for  the  suffixes  ic  and  ate,  and  of  proto 
for  ite  or  ous.  The  prefixes  mon,  di  or  bi,  tri  or  ter,  tetra,  and 
penta  are  often  employed  to  indicate  the  number  of  atoms  of 
a  given  element  in  a  compound,  as  CO,,  carbon  dioxid;  HgCl2, 
the  bichlorid  of  mercury;  N203,  nitrogen  trioxid. 

The  oxids  of  some  of  the  metals  are  sometimes  named  by 
simply  changing  the  um  termination  of  the  name  of  the  metal 
to  a;  as  Na20,  soda;  MgO,  magnesia;  and  SrO,  strontia.  Many 
oxids  of  non-metallic  elements  unite  with  H20  to  form  acids, 
and  on  this  account  are  known  as  anhydrids;  thus,  P205  is 
called  phosphoric  anhydrid,  and  C02,  carbonic  anhydrid. 

The  ferric  salts  were  formerly  termed  the  sesquioxid, 
sesquichlorid,  etc.  The  proper. names  of  compound  radicals 
commonly  terminate  in  yl,  as  CO,  carbonyl;  HO,  hydroxyl; 
N02,  nitroxyl;  and  S02,  sulphuryl.  The  popular  names  of 
common  compounds  do  not  generally  express  their  composition, 
but  more  often  the  place  of  origin  or  some  physical  peculiarity; 
for  example,  ammonia,  marsh-gas,  sewer-gas,  and  oil  of  vitriol. 


ACIDS,  BASES,  AND  SALTS. 

An  acid  is  a  chemic  compound  consisting  of  a  negative 
element  (rarely  metals)  united  to  H  either  directly  or  by  means 
of  linking  0  or  S.  If  the  union  is  direct,  we  have  what  is  called 
a  hydracid;  if  by  the  medium  of  0  as  a  connecting  agent,  an 
oxyacid;  if  S  is  the  linking  agent,  a  sulpho-acid.  The  oxyacids 
are  much  the  most  numerous.  The  following  graphic  formulas 
show  how  0  and  S  act  as  linking  agents: — 

Carbonic  acid  Sulphocarbonic  acid 

H— o—  r\  H— s—  r\ 

H  —  O—  I  H  — S— I 

o  =  V-y  s=v^ 


ACIDS,  BASES,  AND  SALTS.  81 

Ternary  acids  may  be  regarded  as  hydrates  of  negative 
elements. 

If  the  number  of  HO  groups  equals  the  valence  of  the 

-  atom  or  atoms,  we  have  an  ortho-acid.     Thus,  SVI(HO)6  is 

orthosulphuric  acid.    Ortho-acids  are  unstable,  tending  to  lose 

1  or  more  molecules  of  water,  leaving  1  atom  of  0  for  every 

2  hydroxyl  groups  that  break  off  H20.     Thus,  orthosulphuric 
acid,  by  losing  2  molecules  of  H20,  becomes  SVI02(HO)2,  which 
is  ordinary  sulphuric  acid,  H2S04.     Acids  derived  from  the 
ortho-acids  in  this  way  are  known  as  meta-acids.     The  meta- 
acids  are  more  stable  than  the  ortho-acids,  and  are  hence  more 
frequently  met  with.     The  strongest  acids  are  generally  those 
in  which  the  acidic  (negative)  element  exerts  a  high  polarity- 
value;   thus,  the  valence  of  S  is  6  in  sulphuric  acid. 

The  properties  of  acids  in  general  are  briefly  as  follows: — 

1.  Dilute  solutions  have  a  sour  taste;   example,  vinegar. 

2.  They  change  litmus  and  other  vegetable  colors  from 
blue  to  red. 

3.  They  corrode  metals,  with  evolution  of  the  H  of  the 
acid,  the  metal  taking  the  place  of  the  H,  forming  salts. 

4.  They  neutralize  bases,  with  the  production  of  salts  and 
water. 

5.  On  living  tissues  they  have  either  an  astringent  or  a, 
caustic  effect,  according  to  the  strength  of  the  acid  or  the 
degree  of  dilution. 

The  H  of  an  acid  which  can  be  replaced  by  metals  to  form 
salts  is  termed  the  basic  hydrogen  (since  it  plays  the  -)-  role), 
and  in  empiric  formulas  is  generally  written  first,  apart  from 
the  H  of  the  compound  radical,  if  such  there  be.  By  the  basic- 
ity of  an  acid  is  meant  the  number  of  atoms  of  basic  hydro- 
gen. Thus,  HC2H302  is  monobasic,  H2C204  is  dibasic,  and 
H3C6H507  is  tribasic. 

A  base  consists  of  a  -f-  element  (metal)  united  to  H  by 
means  of  linking  0.  Otherwise  stated,  a  base  is  a  hydrate  of 
a  metal.  Bases  are  nearly  always  ortho  in  character:  i.e.,  the 
number  of  HO  groups  equals  the  valence  of  the  positive  atom 
or  atoms.  Inorganic  bases  are  commonly  called  hydrates  or 
hydroxids.  Strong  bases  are  sometimes  known  as  alkalies.  The 
strongest  bases  are  those  in  which  the  basic  (positive)  element 
is  of  a  low  polarity-value:  e.g.,  K1  —  0  —  H. 

The  properties  of  bases  are,  in  general,  the  opposite  of 
those  of  acids: — 

1.  Dilute  solutions  have  an  "alkali"  taste. 

2.  They  restore  the  blue  color  of  litmus  and  other  vege- 
table products. 


82  CHEMIC  PHILOSOPHY. 

.3.  They  corrode  some  of  the  less  +  metals,  evolving  H 
and  forming  salts. 

4.  They  neutralize  acids,  producing  salts  and  water. 

5.  On  living  tissues  they  exert  a  caustic  effect,  blistering 
and  forming  soap  with  the  fats. 

The  number  of  replaceable  H  atoms  in  a  base  determines 
its  so-called  acidity.  Thus,  KHO  is  monacid;  Ba(HO)2  is  diacid. 

A  salt  consists  of  a  —  element  joined  to  a  -j-  element, 
either  directly  or  by  means  of  linking  0  or  S.  Salts  are  formed 
in  five  ways: — 

1.  By  the  union  of  a  +  and  a  —  element,  as: — 

Au  +  01,  =  AuCl3 

2.  By  the  union  of  a  -f-  oxid  and  a  —  oxid: — 

CaO  +  C02  =  CaC03 

3.  By  the  union  of  an  acid  and  a  base: — 

HC1  +  KHO  =  KC1  +  H20 

4.  By  the  action  of  an  acid  or  a  base  on  a  metal: — 

Zn  +  H2S04  =  ZnS04  +  H2 

5.  By  substitution  of  one  radical  for  another: — 

AgN03  +  NaCl  =  NaN08  +  AgCl 

This  is  by  far  the  most  frequent  method  of  preparing  salts. 

When  the  basic  H  of  an  acid  is  all  replaced  by  a  metal, 
we  have  a  neutral  or  normal  salt.  ZnS04  is  an  example  of  a 
normal  salt,  in  which  1  atom  of  the  diad  Zn  has  taken  the 
place  of  the  2  atoms  of  H  in  H2S04.  If  the  acid  is  in  excess 
and  its  basic  H  is  only  partially  replaced  by  the  +  element, 
we  have  an  acid  or  bisalt  (so  called  because  the  proportion  of 
acid  radical  to  metal  is  twice  what  it  is  in  normal  salts).  Of 
this  class,  NaHC03  is  an  example,  being  derived  from  H2C03 
by  the  substitution  of  1  atom  of  Na  for  1  of  the  2  of  H. 

When  part  of  the  basic  H  of  an  acid  is  replaced  by  one 
metal  and  part  by  another,  we  have  what  is  called  a  double 
salt,  of  which  KNaS04  is  an  example.  Basic  or  subsalts  are 
formed  when  the  base  is  in  excess  of  the  acid  with  which  it 
is  combined,  leaving  part  of  the  0  or  HO  of  the  base  undis- 
turbed. 

=  0 
—  NO, 


Bi 


is  the  most  important  basic  salt,  corresponding  to  the  neutral 
or  saturated  salt  Bi(N03)3.     Subsalts  are  generally  unstable; 


ACIDS,  BASES,  AND  SALTS.  83 

hence  of  uncertain  composition.  Persalts  are  ready  oxidizers, 
and  deflagrate  on  heating.  Hyposalts  are  strong  reducing 
agents. 

By  the  chemic  reaction  of  a  substance  in  the  fluid  form 
we  mean  the  change  of  color  produced  in  litmus-paper  im- 
mersed in  the  liquid.  If  the  change  is  from  red  to  blue,  the 
reaction  is  alkaline;  if  the  reverse,  acid.  When  neither  color 
is  changed,  the  reaction  is  neutral.  In  a  few  instances — e.g., 
cows'  milk — the  reaction  is  amphoteric,  changing  blue  litmus 
to  red  and  red  to  blue.  This  paradox  is  explained  by  the  pres- 
ence of  different  salts  of  an  alkaline  and  of  an  acid  reaction. 

The  terms  neutral,  acid,  and  basic  as  applied  to  the  com- 
position of  the  salt  molecule  do  not  necessarily  signify  a  similar 
chemic  reaction.  A  strong  acid  with  a  weak  base  will  form 
salts,  as  a  rule,  all  of  acid  reaction;  for  this  reason  the  sul- 
phates generally  are  acid  in  nature  and  hence  astringent. 
Conversely,  a  weak  acid  and  a  strong  base  yield  salts  of  alka- 
line reaction.  The  acid  or  bicarbonate  of  sodium,  for  instance, 
is  used  largely  as  an  antacid  on  account  of  its  alkaline  reaction. 
The  salts  of  the  hydracids  are  usually  neutral  in  composition 
and  reaction. 

For  convenience  of  comparison,  it  is  said  that  acids,  bases, 
and  salts  are  built  upon  the  water  (H  —  0  —  H)  type.  In  the 
acid  one  of  the  H  atoms  is  replaced  by  a  —  element,  expressed 

thus:  E  —  0  —  H.    In  the  base  a  +  element  is  substituted  for 

+ 

the  H  atom;  as,  E  —  0  —  H.  In  the  salt  both  H  atoms  are 
displaced,  the  one  by  a  +  element,  the  other  by  a  —  element, 

+ 
represented  thus:   E  —  0  —  E. 

In  organic  chemistry  we  have  three  groups  of  compounds 
corresponding  to  acids,  bases,  and  salts,  and  termed  amids, 
amins,  and  alkalamids,  respectively.  In  these  N"  acts  as  the 
linking  element  instead  of  0  or  S.  These  compounds  are  said 
to  be  built  upon  the  ammonia  (H3N)  type.  P  and  As  also  rarely 
act  as  linking  agents. 

According  to  the  theory  of  electrolytic  dissociation,  now 
well  established,  dilute  aqueous  solutions  of  electrolytes  con- 
tain no  molecules,  but  only  cations  and  anions.  Thus,  a  weak 
solution  of  NaCl  breaks  up  into  the  cation  Na  and  the  anion 
Cl;  one  of  KBr  into  K  and  Br.  Hence,  a  mixture  of  these 
solutions  has  the  same  properties  as  a  mixture  of  solutions  of 

+ 

similar  strength  of  KC1  and  NaBr.  Acids  dissociate  into  a  H 
cation  and  an  anion  varying  with  each  acid,  and  the  strength 


84  CHEMIC  PHILOSOPHY. 

of  any  acid  depends  upon  the  number  of  H  ions  present.    Bases 

dissociate  into  (HO)  anions  and  various  metals.  The  H  and 
the  HO  ions  cannot  exist  independent  in  the  same  solution, 
but  unite  to  form  H20,  the  other  ions  remaining  unchanged. 
Most,  if  not  all,  chemic  reactions  are  ionic  in  character,  and 
some  of  the  biologic  effects  of  acids  and  bases  have  been  proved 
to  depend  solely  upon  the  H  ions  of  the  acid  and  the  HO  ions 
of  the  base.  Acids  tend  to  decrease  the  secretions  of  acid 
glands  and  increase  alkaline  secretions,  while  alkalies  have  just 
the  opposite  effects. 


CHEMIC  REACTIONS  AND  EQUATIONS. 

By  chemic  reaction  is  understood  the  mutual  action  on 
each  other  of  the  factors  in  a  chemic  change.  A  substance 
added  to  another  to  produce  such  a  change  is  called  a  reagent. 

Experiment. — Add  BaCl2  to  MgSO4  and  note  turbidity. 

In  this  reaction  BaCl2  is  the  reagent  used  as  a  test  for 
sulphates;  the  factors  in  the  reaction  are  BaCl2  and  MgS04; 
the  products  of  the  reaction  are  BaS04  and  MgCl2. 

The  burning  of  coal  or  wood  is  another  example  of  chemic 
reaction,  in  which  the  factors  are  the  0  of  the  air  and  the 
C  and  H  of  the  fuel,  the  products  being  H20  and  C02.  In  every 
chemic  reaction  heat  is  a  result;  light  is  also  a  result  if  the 
chemic  action  is  sufficiently  strong. 

Chemic  reaction  is  favored  by  everything  that  aids  a  free 
mixture  of  the  molecules  of  the  factor  substances:  that  is,  by 
heat,  light,  electricity,  fusion,  solution,  volatilization,  and  pul- 
verization. 

The  reagent  for  a  given  substance  or  class  of  substances 
is,  of  course,  a  test  for  that  substance  or  class,  as  well  as  an 
antidote  in  the  case  of  poisons.  Thus,  BaCl2  is  the  test-reagent 
for  sulphates  in  general,  as  it  forms  with  them  the  insoluble 
sulphate  of  barium;  AgN03  is  the  test-reagent  for  chlorids; 
and,  conversely,  common  salt  (NaCl)  is  the  chemic  antidote  for 
poisoning  by  AgN03. 

Experiment. — Show  ppt.  of  AgNO3  with  NaCl. 

A  precipitate  (ppt.)  is  a  substance  thrown  out  of  solution. 
In  the  above  example  AgCl  is  the  ppt.  In  manufacturing 
chemistry  precipitation  is  a  common  method  of  preparing 
drugs.  The  ppts.  produced  by  hot,  strong  solutions  are  gen- 
erally denser,  coarser,  and  heavier  and  more  often  crystalline 
than  those  produced  in  cold,  dilute  solutions. 


STOECHIOMETRY.  85 

A  chemic  equation  is  the  statement,  by  means  of  formulas 
and  of  +  and  =  signs,  of  the  equality  between  the  sum  of  the 
factors  and  the  sum  of  the  products  of  a  chemic  reaction.  The 
equation  represents  the  reaction  between  molecules,  and  con- 
sequently between  the  homogeneous  substances  which  the 
molecules  constitute.  It  also  shows  the  numeric  balance  of 
molecular  weights,  thus: — 

137  +  71  +  24  +  32  +  64  =  137  +  32  +  64  +  24  +  71 
BaCl2  +  MgS04  =  BaS04  +  MgCl2 

There  are  a  few  simple  rules  in  regard  to  the  writing  of 
chemic  equations: — 

1.  Positives  combine  with  negatives,  and  negatives  with 
positives. 

2.  Only  whole  molecules  are  represented. 

3.  The  valence  of  atoms  and  radicals  must  be  fully  satis- 
fled. 

4.  It  is  customary  to  indicate  the  ppt.  (if  any)  by  under- 
lining its  formula. 

Chemic  equations  are  used  to  represent  three  general  kinds 
of  reaction: — 

1.  Simple  union  of  elements  or  compounds: — 

H2  +  C12  =  2HC1 
CaO  +  C02  =  CaC03 

2.  Decomposition    of    a    complex    molecule    into    simpler 
ones: — 

CaC03  =  CaO  +  C02 

3.  Eeaction  between  two  or  more  molecules,  with  inter- 
change of  atoms  or  radicals: — 

2KI  +  HgCl2  =  HgI2  +  2KC1 
This  class  is  by  far  the  most  common. 


STOECHIOMETRY. 

Since  the  molecular  weight  of  any  compound  denotes  a 
definite  amount,  it  is  easy  to  compute,  by  simple  proportion, 
the  exact  percentage  of  any  of  the  component  elements.  Again, 
in  a  similar  manner,  we  can  readily  determine  from  the  weight 
given  of  any  of  the  members  of  the  equation  the  weight  re- 
quired of  any  other  member.  The  proportion  should  be  first 


86 


CHEMIC  PHILOSOPHY. 


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QUESTIONS.  87 

stated  with  formulas.     Thus,  let  it  be  required  to  find  how 
much  zinc  oxid  can  be  obtained  from  100  gm.  of  zinc: — 

Zn  :  ZnO  :  :  100  :  x 

65  :  81  :  :  100  :x 
Answer  is  124  8/13  gm. 

Such  calculations  are  of  immense  importance  in  manu- 
facturing chemistry.  The  branch  of  the  science  that  they  con- 
stitute is  known  as  stoechiometry.  The  unit  of  weight  for 
gases  is  the  crith  (0.0896  gm.),  the  weight  of  a  liter  of  H  in  a 
vacuum  at  0°  and  760  mm.  pressure. 


THE  PERIODIC  LAW. 

The  most  satisfactory  classification  of  the  elements  is 
that  of  Mendelejeff,  which  is  based  upon  the  atomic  weights. 
He  observed  that  the  first  seven  elements  after  H  were  repre- 
sentative of  as  many  groups  of  similar  elements.  Each  of  these 
is  put  at  the  head  of  a  vertic  column,  inclosing  the  elements 
which  it  resembles.  The  lateral  rows,  or  series,  or  small  peri- 
ods, two  of  which  make  a  large  period,  run  in  the  orders  of 
the  atomic  weights,  with  a  few  breaks  here  and  there.  It  will 
be  noted  that  alternate  numbers  of  the  same  group  resemble 
each  other  more  than  do  adjacent  numbers.  With  the  aid  of 
this  table  its  author  predicted  the  properties  of  Ga,  Ge,  and 
Sc  while  these  elements  were  still  undiscovered.  Doubtless  the 
other  vacant  places  will  be  filled  in  time.  Group  VIII  is  made 
to  include  a  number  of  intermediate  elements  which  may  later 
be  arranged  in  a  set  of  groups. 

QUESTIONS   ON  THEORETIC   CHEMISTRY. 

1.  Name  and  give  symbols  of  ten  elements  whose  names  begin 
with  C. 

2.  Name  five  elements  which  have  both  an  English  and  a  Latin 
name. 

3.  Name  a  liquid  element. 

4.  Peroxid  of  hydrogen  gives  off  atomic  O.     Is  this  more  or  less 
active  than  the  atmospheric  O? 

5.  Why  does  NaCl  dialyze  more  readily  than  Gaell^O.™? 

6.  What  is  the  density  of  As  in  the  gaseous  state? 

7.  Why  is  density  always  one-half  the  molecular  weight? 

8.  Calculate  from  the  table  the  molecular  weight  of  H2S04,  avoid- 
ing fractions  and  using  the  nearest  whole  numbers. 

9.  What  is  the  most  important  distinction   between   metals  and 
metalloids  ? 


88  CHEMIC  PHILOSOPHY. 

10.  Which  is  likely  to  be  more  stable:  a  compound  of  O  and  N  or 
one  of  0  and  As? 

11.  What  element  is  the  unit   of  valence,  atomic  and  molecular 
weight,  and  density? 

12.  Why  does  0  enter  into  more  chemic  combinations  than  any 
other  element? 

13.  Name  a  monad,  a  diad,  a  triad,  a  tetrad,  a  pentad,  a  hexad,  a 
heptad,  and  an  octad. 

14.  What  element  has  the  highest  atomic  weight,  and  how  much 
is  it? 

15.  Why  should  we  expect  P  rather  than  Hg  to  show  allotropic 
tendencies? 

16.  Why  do  elements  combine  in  simple  proportions? 

17.  Give  reasons  for  the  law  of  even  numbers. 

18.  Write    formulas    of    potassium    iodid,    calcium    oxid,    mercuric 
chlorid,  carbon  dioxid,  and  sulphur  trioxid. 

19.  What  is  the  valence  of  the  radical  Si04,  and  why? 

20.  Write  formula  of  ferric  ferrocyanid ;  of  ferrous  *f  erricyanid. 

21.  Write  graphic  formulas  of  some  acid,  base,  and  salt. 

22.  Name:   (Fe2),(P2O7)3;   (BiO)N03;  Na2B4O7;  HC7H5O3. 

23.  Write  graphic  formulas  of  ferric  chlorid,  mercurous  iodid,  and 
manganic  sulphate. 

24.  Translate  "protiodid  of  mercury,  sesquichlorid  of  iron,  and  ter- 
sulphate  of  iron"  into  modern  chemic  nomenclature. 

25.  Name  and  give  basic  formula  of  a  monobasic,  dibasic,  tribasic, 
tetrabasic,  and  hexabasic  acid. 

26.  Name  a  diacid  base. 

27.  What  two  elements  are  present  both  in  bases  and  in  oxyacids, 
and  in  what  way  as  regards  composition  do  these  two  classes  differ? 

28.  What  substance  is  always  formed  when  an  acid  and  a  base  are 
brought  together? 

29.  Mention  and  give  formulas  of  five  salts,  each  formed  in  a  dif- 
ferent way. 

30.  Name  an  acid  salt  which  is  alkaline  in  reaction. 

31.  Write  equation  for  reaction  between  CaS04  and  Na2C03. 

32.  Find  percentage  by  weight  of  O  in  H20. 

33.  Find  percentage  by  weight  of  Ca  in  CaCO3. 

34.  What  percentage  by  weight  of  CO2  gas  is  given  off  on  burning 
limestone  (CaCO3)? 

35.  How  much  AgN03  can  be  made  from  108  grams  of  silver? 

36.  How  much  NaCl  is  required  to  make  500  gm.  of  HC1?     (2NaCl 
+  H2S04  =  2HC1  +  Na2S04.) 

37.  What  is  the  volume  of  a  kg.  of  H  at  standard  temperature  and 
pressure  ? 

38.  Calculate  the  percentage  composition  of  potassium  nitrate. 

39.  What  is  the  weight  of  a  liter  of  O? 

40.  What  weight  of  NaHO  is  required  to  neutralize  a  mg.  of  HC1? 


INORGANIC  CHEMISTRY. 


METALS. 

THESE  are  solid  substances  (except  mercury  and  hydro- 
gen), electropositive,  and  good  conductors  of  heat  and  elec- 
tricity. Their  oxids  form  bases  with  H20. 

DISCOVERY  AND   DERIVATION. 

Au,  Ag,  Hg,  Sn,  Cu,  Zn,  Pb,  and  Fe  were  known  to  the 
ancients.  The  corresponding  Latin  names  from  which  the 
symbols  were  derived  are  aurum  (color  of  fire),  argentum 
(white),  hydrargyrum  (liquid  silver),  stannum  (stone),  cuprum 
(island  of  Cyprus),  zincum  (German,  zinn  or  tin),  plumbum 
(heavy),  and  ferrum.  Antimony  (from  anti  and  moine,  because 
some  monks  were  poisoned  with  it;  stibi  is  the  Greek  name 
for  native  sulphid)  and  bismuth  (German  wismuth,  meaning 
variegated  tints)  were  discovered  in  the  latter  part  of  the 
fifteenth  century.  Arsenic  (male  or  strong)  was  discovered  by 
Schroder  in  1694;  cobalt  (mine-demon)  by  Brandt  in  1733; 
platinum  (little  silver)  by  Wood  in  1741;  nickel  (worthless) 
by  Cronstadt  in  1751;  manganese  (confounded  with  Mg)  by 
Galm  in  1774;  molybdenum  (Greek  for  lead)  by  Hjelm  in 
1782;  and  chromium  (color)  by  Vanquelin  in  1797.  Humphry 
Davy  in  1807  and  1808  first  separated  K,  Na,  Ca,  Ba,  Sr,  and 
Mg  from  their  oxids.  The  first  element  is  so  called  from  pot- 
ash, and  its  symbol  is  derived  from  kali,  the  Arabic  word  for 
ashes.  Sodium  refers  to  soda-ash;  natrium  to  natron,  the  old 
name  for  natural  deposits  of  Na2C03.  Calx  is  the  Latin  name 
for  lime,  or  CaO.  Barium  is  of  Greek  origin,  and  means  heavy. 
Strontium  is  named  after  the  Scottish  village  Strontian,  where 
SrC03  was  first  found.  Magnesium  derives  its  name  from  Mag- 
nesia in  Asia  Minor.  Cadmium  (from  calamine)  was  isolated 
by  Stromeyer  in  1817;  lithium  (stone)  by  Arfvedsen  in  1817; 
and  aluminum  (from  alum)  by  Wohler  in  1828. 

Many  metals  have  been  named  after  persons,  places,  and 
deities:  for  example,  cerium  after  the  goddess  Ceres;  colum- 
bium  or  niobium  after  Columbia  and  Niobe;  gadolinium  after 
John  Gadolin;  gallium  from  Gaul;  germanium  from  Germany; 
masrium  from  the  Arabic  name  of  Egypt;  palladium  after 

(89) 


90  INORGANIC  CHEMISTRY. 

Pallas;  ruthenium  from  the  Latin  name  of  Kussia;  scandium 
after  Scandinavia;  tantalum  after  Tantalus;  terbium,  ytter- 
bium, and  yttrium  after  Ytterby  in  Sweden;  thorium  after 
Thor;  thulium  after  Thule;  titanium  after  the  Titans;  ura- 
nium after  the  planet  Uranus;  and  vanadium  after  the  Van 
goddess  Vanadis.  Some  are  named  after  the  color-lines  seen 
in  the  spectroscope,  as  cesium,  bright  blue;  indium,,  indigo; 
rubidium,  red;  thallium,  green.  Others  take  their  names  from 
some  physic  properties  of  the  metal  or  its  salts:  e.g.,  glucinum, 
sweet;  iridium,  rainbow;  rhodium,  rosy;  lanthanum,  unseen; 
osmium,  odor;  samarium,  samarskite;  tellurium,  earth;  tung- 
sten, from  the  Swedish,  meaning  weighty  stone;  wolf  ram,  mean- 
ing wolf-cream;  and  zirconium,  jargon.  Ammonium  was  so 
called  after  Jupiter  Ammon,  near  whose  temple  in  Libya  the 
Arabs  of  the  desert  long  ago  made  NH4C1  by  distilling  camels' 
dung  as  a  substitute  for  common  salt.  Praseodymium  (garlic) 
and  neodymium  (new)  are  derived  from  didyniium  (double) 
which  was  formerly  believed  to  be  an  element,  but  is  really  a 
mixture  of  the  two  metals  first  mentioned. 

ORDINARY   SOURCES   OF  METALS   IN   NATURE. 

Gold:    river-beds   and  rock-veins;    always   free   except   as 

tellurid. 

Platinum  and  Pd,  Rh,  Ir,  Ru,  and  Os:  river-beds. 
Bismuth:  also  as  oxid  and  sulphid. 
Free  State  \   Silver:  also  as  sulphid,  chlorid,  and  tellurid. 
Mercury:  minute,  disseminated  globules. 
Copper:  cubes  and  octahedra;  usually  oxids,  sulphates,  and 

carbonates ;  also  found  in  hulls  of  various  grains. 
[  Arsenic:  rarely  free  in  lamellar,  kidney-shaped  masses. 

Chlorids  are  commonly  known  as  horn;  sulphids  as  glance. 
COMBINATION. 

Light  Metals. — Sp.  gr.  below  4. 

The  Alkali  Metals. — On  account  of  the  ready  solubility  of 
their  salts,  they  are  not  found  to  a  great  extent  as  ores,  and 
never  occur  in  a  free  state.  K  is  obtained  as  carbonate  from 
the  ashes  of  land-plants  (sugar-cane,  beet-root,  marc,  etc.); 
also  from  the  double  chlorid  of  K  and  Mg  (carnallite),  which 
is  extensively  mined  at  Stassfurt,  Germany.  K  compounds, 
especially  the  carbonate,  constitute,  by  weight,  about  one-third 
of  sheep's  wool,  and  are  essential  ingredients  of  all  the  formed 
elements  of  the  human  body.  Na  is  very  abundant  as  the 
chlorid  arid  the  sulphate  in  all  soils  and  natural  waters  and  in 
atmospheric  dust.  The  silicate  of  Na  is  present  in  the  tissues 
of  plants;  the  chlorid,  phosphate,  and  carbonate  are  very  nee- 


EXTRACTION  OF  METALS.  91 

essary  ingredients  of  the  blood  and  its  secretions.  Li  salts 
arc  comparatively  rare.  They  are  found  in  mineral  springs 
mid  are  also  obtained  from  the  ashes  of  the  beet  and  tobacco. 
NH3  is  present  in  decaying  nitrogenous  matter  generally:  e.g., 
in  barn-yard  manure.  The  chief  commercial  sources  of  NH4 
compounds  are  the  guano-beds  of  South  America  and  the  am- 
moniacal  liquors  obtained  as  a  by-product  from  coke-,  iron-, 
and  gas-  works.  Cs  and  Kb  are  both  very  rare  metals  and  of 
no  present  practical  importance. 

Alkaline  Earths  and  Mg. — These  occur  chiefly  as  sulphates, 
carbonates,  and  silicates.  Next  to  Al,  Ca  is  the  most  abundant 
terrestrial  metal,  being  present  in  all  soils  and  natural  waters, 
and  hence  in  the  tissues  and  juices  of  plants  and  animals.  Sr 
is  found  in  small  amounts  in  sea-water  and  sea-plants  (Fucus 
vesiculosus)  and  in  certain  mineral  springs,  as  well  as  in  ores. 
Ba  is  found  only  in  combination,  and  may  be  obtained  in  small 
quantities  from  the  ashes  of  sea-plants  and  of  some  trees,  par- 
ticularly the  beech.  The  metal  Mg  is  never  found  free.  In 
combination  it  is  widely  distributed,  usually  with  Ca.  Mg  salts 
are  present  in  plants  in  considerable  quantities. 

Aluminum. — This  metal,  though  never  found  free,  is  the 
most  widely  distributed  in  the  earth's  crust,  making,  as  it  does, 
— in  the  form  of  silicates,  oxids,  hydrates,  and  fluorids, — the 
great  mass  of  common  rocks,  which  in  their  natural  decom- 
position turn  into  clay. 

Heavy  Metals. — Sp.  gr.  above  4. 

SulpJiids  Chiefly.— As,  Sb,  Co,  Ni,  Cd,  Mo,  Hg,  Pb,  and  Cu. 

Oxids  Chiefly. — Sn,  Mn,  and  Cr. 

Sulphid  and  Chlorid. — Ag. 

Sulphids,  Oxids,  and  Carbonates. — Fe  and  Zn. 

Meteoric  Rocks. — Fe  and  Ni. 

Common  Associations. — Co  and  Ni;  Fe  and  Mn;  Cd  and 
Zn;  Ag  and  Pb;  Ca  and  Mg.  Co  and  Ni  are  obtained  almost 
entirely  from  mines  in  Ontario  and  New  Caledonia. 

The  color  of  ordinary  rocks  is  due  to  iron;  also  the  color 
of  blood  and  green  plants. 

Uranium  and  the  radio-active  metal  radium  are  obtained 
from  pitchblende. 

EXTRACTION   OF  METALS. 

Electrolysis.  —  From  fused  chlorids  usually;  Al  (from 
bauxite);  alkali  metals  and  alkaline  earths;  Mg.  Pure  Cu, 
crystal  Au,  and  other  metals  are  obtained  by  electrolysis  by 
suspending  plates  of  the  same  metals  in  solutions  of  their  salts. 


92  INORGANIC  CHEMISTRY. 

Decomposition  with  metallic  Na  or  K;  weaker  metals 
driven  from  their  combinations;  Mg,  Al,  Ca,  B,  Sr,  U. 

Roasting,  usually  with  sulphids  or  oxids,  and  reduction 
with  charcoal,  lime,  or  iron  slag. 

Lead.— PbS  +  2PbO  =  3Pb  +  S02.  PbS  +  PbS04  =  2Pb 
+  2S02. 

Another  method  is  to  roast  the  ore  to  form  oxid,  then 
combine  with  silica,  and  reduce  this  silicate  in  a  blast  furnace 
with  reduced  iron-ore. 

Mercury.  —  HgS  +  02  =  Hg  +  S02.  Iron  is  sometimes 
added.  Collect  under  H20,  strain  through  linen  or  chamois, 
and  distill. 

Copper.— 2Cu20  +  Cu2S  =  3Cu2  +  S02.  Ore  is  fused  with 
a  siliceous  flux,  sometimes  containing  CaF2.  The  resulting 
"blister  copper"  contains  some  Cu20,  which  is  removed  by 
fusing  with  coal  and  stirring,  or  by  electrolysis. 

Zinc. — Charcoal  reduction. 

Antimony. — Charcoal  reduction. 

Arsenic. — Charcoal  reduction. 

Manganese. — From  carbonate  or  oxid. 

Chromium. — From  oxids  with  charcoal. 

Tin. — From  oxids. 

Nickel. — Eesulting  "speiss"  is  dissolved  in  HC1,  pptd.  with 
H2C204,  and  reduced  with  lime  and  carbon. 

Cobalt. — Same  as  for  Ni. 

Bismuth. — Fused  (after  roasting)  with  slag,  iron,  and  char- 
coal. Melted  mass  settles  in  two  layers;  the  lower  contains  Bi. 

Alkali  Metals. — Old  method  =  charcoal  reduction  of  car- 
bonate, distilling  metal  and  passing  through  naphtha. 

Fractional  Distillation. — Cadmium. — Separated  from  zinc. 

Zinc. — Oxid  or  carbonate  reduced  with  charcoal  in  iron 
retorts,  and  liberated  metal  distilled  over. 

Mercury. — When  cinnabar  is  heated  with  lime  the  metal 
Hg  volatilizes.  It  can  be  refined  by  redistillation,  and  on  a 
small  scale  by  pouring  the  dirty  metal  through  a  filter-paper 
having  a  small  pin-prick  at  the  bottom. 

Sublimation. — Arsenic  from  mispickel  or  white  arsenic. 

Reduction  of  heated  ore  with  H:  Much  employed  in 
laboratory,  but  not  on  a  large  scale.  Eeduced  iron  is  obtained 
this  way. 

Fe203  +  3H2  =  3H20  +  Fe2 

Special  Methods. — Silver. — The  mode  of  separating  Ag 
from  its  ores  varies  with  the  particular  combination.  There 
are  five  main  processes  employed.  1.  The  electrolytic  method 


EXTRACTION  OF  METALS.  93 

is  applied  to  ores  alloyed  with  Cu  or  CuO.  2.  In  the  amal- 
gamation process,  as  practiced  in  the  United  States  (Washoe 
process),  the  silver  ore  is  ground  with  Hg,  common  salt,  and 
CuS04  (and  sometimes  2  per  cent.  Na  to  prevent  "flouring  or 
sickening"  of  the  Hg).  After  straining  the  Ag  amalgam,  the 
quicksilver  is  separated  by  distillation,  leaving  a  residue  of  Ag. 
3.  Wet  extraction  is  accomplished  by  roasting  ores  containing 
AgS,  Cu,  and  Fe  at  such  a  temperature  as  to  form  the  oxids 
of  Cu  and  Fe  and  the  sulphate  of  Ag.  The  latter  salt  is  sepa- 
rated from  the  insoluble  oxids  by  lixiviation  with  H20,  and 
is  then  pptd.  with  metallic  Cu.  Or  common  salt  is  added  to 
the  ore  before  roasting,  forming  AgCl,  which  is  dissolved  out 
from  the  other  matters  with  Na2S203,  pptd.  with  Na2S  as  a 
sulphid,  and  finally  reduced  by  intense  heat  and  a  current  of 
air.  4.  The  cupellation  process  is  probably  the  most  ancient. 
It  is  applied  to  argentiferous  lead  ores,  which  are  roasted  in  a 
reverberatory  or  blast  furnace.  The  lead  is  largely  oxidized 
and  skimmed  off.  When  Pb  is  in  great  excess,  as  is  generally 
the  case,  it  must  first  be  partly  removed  by  melting  (Pb  fuses 
at  328°,  Ag  at  1040°)  and  fractional  crystallization  on  cooling 
(Pattinson's  process);  or  by  alloying  the  melted  ore  with  18 
parts  Zn  to  1  of  Ag,  then  oxidizing  the  Zn  and  washing  the 
oxid  away  with  H20.  5.  The  rather  recent  cyanid  process  de- 
pends on  the  solubility  of  Ag  in  the  alkaline  cyanids.  Ag, 
obtained  by  any  of  these  methods,  is  rendered  chemically  pure 
by  dissolving  in  HN03,  ppt.  with  HC1,  and  reducing  the  result- 
ing chlorid  with  Na2C03. 

Iron. — This  metal  is  extracted  from  oxids  and  carbonates 
by  reducing  with  alternate  layers  of  coal  and  limestone  in  a 
double,  conic,  fire-clay  blast  furnace.  The  limestone  combines 
with  the  silica  of  the  ore  to  form  a  fusible  glass  (cinder  or 
slag).  C02  is  produced  at  the  bottom  of  the  furnace,  while  the 
CO  formed  in  the  body  of  the  furnace  acts  as  a  reducing  agent. 
The  resulting  molten  Fe  takes  up  some  C  as  it  sinks  to  the 
bottom,  where  it  is  run  off  into  molds  as  cast-  or  pig-  iron.  It 
contains  3  to  6  per  cent.  C,  a  little  Si,  and  traces  of  S,  P,  and 
Mn.  Wrought  Fe  is  nearly  the  pure  metal,  containing  less 
than  V2  of  1  per  cent.  C.  It  is  made  from  cast  Fe  by  a  process 
of  thorough  oxidation  termed  puddling,  conducted  in  a  blast 
furnace  with  constant  stirring.  Steel  contains  from  0.8  to  1.5 
per  cent.  C.  It  is  made  nowadays  chiefly  by  the  Bessemer 
process,  consisting  essentially  of  the  addition  to  molten  wrought 
Fe  of  a  certain  proportion  of  spiegeleisen,  or  ferromanganese, 
which  is  a  mixture  of  white  cast  Fe  with  about  7  per  cent. 
Mn.  The  open-hearth  process  is  similar,  except  that  it  is  per- 


94  INORGANIC  CHEMISTRY. 

formed  on  the  hearths  of  reverberatory  furnaces.  The  requisite 
amount  of  C  is  obtained  by  adding  ferromanganese  or  by  filter- 
ing over  carbon  filters.  Cement  or  crucible  steel  is  made  by 
carbonizing  in  furnaces  wrought  Fe  packed  in  charcoal  and 
siliceous  material.  The  resulting  "blister  steel"  is  melted  in 
crucibles  and  cast  in  small  ingots. 

Gold. — There  are  four  main  processes  of  extraction:  1. 
Placer  mining  (panning,  cradling,  hydraulic  mining),  in  which 
the  Au  is  separated  from  sand  and  earth  by  washing  through 


Fig.  20.— Sectional  View  of  Blast  Furnace. 


troughs  which  contain  Hg  in  hollows  or  on  Cu  plates  to  catch 
the  gold  in  its  downward  passage.  The  Au  and  Hg  are  parted 
by  distilling  in  a  retort.  2.  Stamping  quartz  to  a  fine  powder 
and  then  washing  away  the  lighter  earthy  matter.  3.  The  Cl 
process  for  pyritic  ores,  which  comprises  the  following  steps: 
Roasting,  mixing  with  H20,  and  saturating  with  Cl  for  twelve 
hours  to  form  AuCL,  which  is  pptd.  from  solution  by  adding 
FeS04  or  oxalic  acid,  as  a  fine  brown  powder  (spongy  or  crystal- 
line gold). 


PHYSIC  PROPERTIES  OF  METALS.  95 

6FeS04  +  2AuCl3  =  2Fe2(S04)3  +  Fe2Cl6  +  2Au 
3H2C,04  +  2AuCl3  =  6C02  +  6HC1  +  2Au 

The  ppt.  is  washed,  placed  in  a  crucible  lined  with  borax, 
melted,  and  poured  into  an  ingot.  4.  The  cyanid  process  de- 
pends on  the  solubility  of  the  metal  Au  in  solutions  of  the 
alkaline  cyanids.  Au  is  separated  from  Ag  by  electrolysis  or 
by  dissolving  out  the  latter  with  HN03  or  H2S04.  If  neces- 
sary, before  "parting,"  enough  Ag  must  be  added  to  make 
about  3  to  1  of  Au:  a  procedure  known  as  quartation.  Cu  is 
separated  with  H2S04.  Gold  is  purified  by  dissolving  in  nitro- 
hydrochloric  acid  and  precipitating  with  FeCl2. 

2AuCl3  +  6FeCl2  =  Au2  +  3Fe2Cl6 

The  corrugated  non-cohesive  Au  used  by  dentists  is  said  to  be 
prepared  by  tightly  packing  sheets  of  Au  between  leaves  of 
unsized  paper  in  Fe  boxes,  and  then  heating  sufficiently  high 
to  carbonize  the  paper. 

Platinum. — Deville's  method  of  extraction  consists  in 
melting  the  ore  with  an  equal  weight  of  PbS  and  half  as  much 
Pb,  which  take  away  the  Pt  from  the  other  metals.  This  alloy 
is  then  fused  with  access  of  air;  the  Pb  is  oxidized  and  flows 
off  as  a  slag,  leaving  Pt  as  a  spongy  mass.  This  is  now  melted 
in  a  lime-furnace  by  means  of  the  oxyhydrogeu-blast  lamp,  and 
poured  into  molds.  Pt  black  is  prepared  by  dissolving  the 
metal  in  aqua  regia,  evaporating  excess  of  acid,  then  boiling 
with  a  strong  solution  of  KHO  and  adding  grape-sugar. 

Ammonium. — Free  NH4  can  be  prepared  by  heating  Na 
in  a  sealed  tube  with  NH3  and  then  heating  this  product  with 
XH4C1  in  another  sealed  tube.  NaCl  is  formed,  and  also  a 
dark-blue  lustrous  liquid,  which  soon  decomposes  into  H  and 

NH,. 

Granulated  Metals. — Zinc  and  other  granulated  metals  are 
prepared  simply  by  melting  and  pouring  into  H20.  Zn  becomes 
brittle  when  melted  several  times,  owing  to  formation  of  ZnO 
and  contamination  with  the  Fe  of  the  ladle.  It  can  be  purified 
by  throwing  on  the  molten  metal  some  dry  NH4C1. 


PHYSIC   PROPERTIES   OF   METALS. 

All  are  solid  at  ordinary  temperatures,  except  NH4  and 
Hg,  which  solidifies  at  —39.4°  and  boils  at  357  W*-  H  is 
sometimes  considered  a  gaseous  metal.  Metals  are  electro- 
positive and  opaque,  except  in  very  thin  sheets.  Nearly  all 


96 


INORGANIC  CHEMISTRY. 


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PH. 


S?  = 


§.§.! 


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RELATIVE 
HARDNESS.I 


FUSING- 

POINT  (C.). 


LINEAR 

EXPANSION.2 


HEAT 
CONDUCTION  .3 


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ELECTRIC 
CONDUCTION.* 


b 


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SPECIFIC 
HEAT. 


PHYSIC  PROPERTIES  OF  METALS.  97 

are  sectile:  i.e.,  can  be  cut  without  crumbling.  Metals  occur- 
ring free  in  Nature  are  generally  crystalline,  and  all  probably 
can  be  made  to  crystallize,  cubes  and  octahedra  being  the 
prevailing  types.  When  unoxidized,  they  present  a  shining 
appearance,  called  metallic  luster,  and  are  capable  of  being 
polished. 

Nearly  all  metals  are  more  or  less  white  in  color,  often 
with  a  gray  or  blue  tinge.  Finely  powdered  metals  often  lack 
metallic  luster.  The  alkaline  earthy  metals  are  yellowish. 
Gold  is  yellow  (brown  in  powder);  Cu  red;  powdered  As,  Sb, 
Ag,  Pt,  and  Fe  black.  Bi  and  Co  are  white  with  a  pink  tinge. 
Thin  leaves  of  Au  appear  green  or  purple  by  transmitted  light, 
and  molten  Au  is  bluish  green  in  color.  Cast-iron  is  white  or 
gray,  according  as  the  union  of  Fe  with  graphite  is  chemic  or 
physic.  Heated  Cu  and  freshly-tempered  steel  exhibit  a  rain- 
bow of  colors.  As  and  Sb  are  characterized  by  a  garlicky  odor, 
brought  out  on  heating.  Fe,  Cu,  and  Zn  also  yield  an  odor  on 
heating.  Cu  has  the  most  decided  metallic  taste. 

In  sp.  gr.  metals  vary  from  Li  (0.59)  to  Os  (22.47).  The 
common  alkali  metals  are  lighter  than  H20;  Mg  and  Ca  about 
1 3/4  times  as  heavy;  Al  and  Sr,  2  1/2  times;  and  Ba,  3  3/4. 
These  are  termed  the  light  metals.  The  remainder  have  a  sp. 
gr.  above  6  (see  table)  and  are  called  heavy  metals.  The  sp.  gr. 
of  Fe  is  less  the  more  C  it  contains:  wrought  iron,  7.8;  steel, 
7.6  to  8;  cast-iron,  7.1.  Cast  metals  are  a  little  lighter  than 
the  same  in  wire  or  wrought. 

Experiment. — Float  a  piece  of  Fe  on  Hg. 

In  hardness  metals  vary  greatly.  The  alkali  metals  are 
waxy  and  are  easily  cut  with  a  knife.  Of  common  every-day 
metals  Pb  is  softest,  and  hence  is  often  taken  as  the  unit  of 
hardness  (see  table).  It  cuts  readily,  and  when  rubbed  on  a 
piece  of  white  paper  leaves  a  gray  streak.  Sn  can  also  be 
scratched  with  the  finger-nail.  Fe  and  Cu  are  2.4  times  as  hard 
as  Pb,  and  Ni  2.5  times  as  hard,  being  the  hardest  common 
metal.  Ir  is  the  hardest  metal  and  scratches  the  best  steel. 
Au  and  Ag  are  too  soft  alone  for  commercial  use;  hence  they 
are  alloyed,  the  former  with  Ag  (pale  or  green  gold)  or  Cu 
(red  gold),  the  latter  with  Cu.  Au  is  also  toughened  by  fusing 
with  a  flux  of  1  part  each  charcoal  and  ISTH4C1  added  to  the 
gold  just  before  melting. 

Aside  from  Hg,  the  lowest  f.p.  is  that  of  Ga  (30°),  and 
next  to  this  come  Eb  (38.5°),  K  (62.5°),  and  Na  (95.6°).  Also 
fusible  below  a  red  heat  are  Li,  Sn,  Bi,  Cd,  Pb,  Zn,  Mg,  Sb, 
and  Al.  Metals  of  the  alkali  earths  melt  at  a  red  heat.  Ag, 


98  INORGANIC  CHEMISTRY. 

Cu,  and  Au  require  a  bright-red  or  white  heat  to  melt  them. 
The  f.p.  of  Fe  varies  inversely  with  the  percentage  of  C  it  con- 
tains. That  of  cast  Fe  is  about  1200°;  steel,  1400°;  wrought 
Fe,  1600°;  Ni,  Co,  and  Pd  likewise  require  a  high  forge-heat 
to  melt  them,  while  Or,  U,  Mo,  and  W  do  not  melt  in  the  forge, 
but  agglomerate.  Pt,  Ce,  Ir,  and  Os  are  infusible  in  the  ordi- 
nary blast  furnace,  but  are  melted  by  the  oxyhydrogen  blow- 
pipe. Fe  and  Pt  become  semiliquid  or  pasty  on  heating  suffi- 
ciently, and  hence  can  be  welded.  Alloying  with  other  metals 
lowers  the  m.p.  Mg,  Zn,  and  metals  of  the  alkalies  and  alkaline 
earths  burn  easily.  As  and  Hg  are  quite  volatile,  and  Cd,  Zn, 
and  Pb  volatilize  at  a  red  heat  or  higher.  Sb  and  Bi  have  the 
peculiar  property  of  expanding  on  cooling. 

As  shown  by  the  table,  each  metal  expands  at  a  definite 
rate  on  heating  a  given  number  of  degrees.  Metals  as  a  class 
are  good  conductors.  Ag  ranks  first  in  conducting-power,  both 
for  heat  and  electricity,  with  Cu  a  close  second.  Bi  stands  at 
the  bottom  in  these  respects.  The  specific  heat  of  common 
metals  ranges  from  Bi  (0.0308)  to  Na  (0.2934).  Al  requires 
about  twice  as  long  to  reach  the  same  temperature  as  Fe. 

In  tenacity  the  more  fibrous  metals  (Co,  Ni,  Fe,  Cu)  lead. 
Pb  ranks  very  low  in  this  property.  As,  Sb,  Bi,  Mn,  and  Zn 
are  noted  for  their  brittle  character.  The  last  named  is  made 
malleable  by  heating  to  120°-150°;  it  becomes  brittle  again  at 
205°.  Wrought  Fe  is  the  softest  and  toughest  of  the  three 
forms  of  Fe.  It  is  quite  malleable  when  heated.  When  heated 
steel  is  cooled  rapidly  it  becomes  hard  and  brittle;  if  cooled 
slowly  it  retains  its  elasticity  as  well  as  hardness,  and  may  be 
forged  and  welded.  It  is  tempered  by  heating  to  220°  or  320° 
and  cooling  slowly.  Fe  and  Au  increase  in  tenacity  at  100°; 
less  so  above  this.  Au  is  first  and  Ag  second  in  malleability 
and  ductility.  These  properties  of  Au  are  much  impaired  by 
even  minute  traces  of  Pb,  Bi,  or  Sb.  Great  cold  renders  all 
metals  more  brittle.  Annealing,  or  heating  and  cooling,  re- 
stores the  normal  malleability  and  ductility  lost  by  working. 
Metals  are  generally  deficient  in  elasticity,  except  steel.  The 
addition  of  a  small  proportion  of  Pt  to  Au  greatly  increases  the 
elasticity  of  the  latter.  The  more  elastic  metals  are  generally 
sonorous.  Sn  and  Cd  crackle  ("cry")  when  bent,  owing  prob- 
ably to  the  friction  of  their  crystals.  Metals  and  their  alloys 
tend  to  become  crystalline  on  percussion  and  other  mechanic 
forces. 

Fe  is  paramagnetic;  Mn,  Ni,  Cr,  and  Co  slightly  so.  Bi 
is  the  most  diamagnetic  metal.  Al  and  Mg  are  permeable  to 
the  x-rays.  Many  metals  in  the  molten  state  absorb  or  occlude 


CHEMIC  PROPERTIES  OF  METALS.  99 

0,  giving  it  off  again  on  cooling,  sometimes  with  "spitting"  of 
the  metal. 

Metals,  like  the  metalloids,  sometimes  assume  different  ap- 
pearances and  other  properties  or  allotropic  forms.  As,  for 
example,  has  a  steel-gray  crystalline  and  two  amorphous  (friable 
black  and  gray)  forms.  Ag  may  assume  a  white,  black,  blue, 
bluish-green,  red,  purple,  or  yellow  color. 


CHEMIC   PROPERTIES   OF  METALS. 

The  lighter  metals  are,  generally  speaking,  more  active 
chemically  than  the  heavy  metals. 

Solubility. — HN03  dissolves  all  metals  except  Al,  Au,  Pt, 
Sb  (forms  antimonic  acid),  and  Sn  (forms  white  metastannic 
acid).  Pb,  Ag,  and  Fe  are  soluble  in  dilute,  but  not  in  strong, 
HNOa.  When  Fe  is  immersed  in  the  strong  acid,  it  is  rendered 
passive:  i.e.,  incapable  of  being  dissolved  in  the  weaker  acid 
unless  heated  or  unless  some  other  metal — as  Cu,  Ag,  or  Pt — 
is  also  present.  If  Pt  is  alloyed  with  Ag,  HN03  dissolves  it. 
A  gold-silver  or  gold-copper  alloy  containing  less  than  25  per 
cent.  Au  is  disintegrated  by  HN03,  which  dissolves  the  other 
metal,  leaving  Au.  If  there  is  more  than  25  per  cent.  Au, 
enough  Ag  or  Cu  must  be  fused  with  the  alloy  (quartation) 
before  the  acid  will  remove  all  the  Cu  or  Ag. 

HC1  dissolves  all  metals  except  Sb,  Hg,  Ag,  Pb,  Au,  Pt, 
and  Bi. 

Dilute  H2S04  dissolves  all  except  Sb,  Al  (soluble  on  boil- 
ing), Pb  (slightly),  Au,  Pt,  Cu,  and  Hg  (soluble  in  concen- 
trated). Strong  II2S04  forms  a  coating  of  sulphate,  which,  not 
being  dissolved  away,  soon  stops  chemic  action. 

Aqua  regia  dissolves  Au  (quickly),  Pt  (slowly),  and  Sb 
(also  soluble  in  hot  HC1  and  in  hot  H2S04). 

Insoluble  in  acids  are  Cr,  Rh,  Ir,  and  Ru. 

The  metals  replace  and  set  free  H  in  acids,  forming  salts. 

Caustic  alkalies  dissolve  the  weaker  metals,  Zn,  Al,  and 
Sn,  forming  zincates,  aluminates,  and  metastannates. 

NaCl  and  organic  acids  dissolve  Zn  (often  contains  As). 
KCN  dissolves  Au,  Ag,  and  Cu.  Al  is  dissolved  by  certain 
vegetable  acids,  especially  in  the  presence  of  N"aCl.  Ammonia- 
water  dissolves  Cu  slowly,  the  process  being  hastened  by  allow- 
ing access  of  air.  Cu  is  also  attacked  by  vegetable  acids  in  the 
presence  of  air  and  moisture;  hence  culinary  preparations 
containing  vinegar  or  lemon-juice  should  not  be  placed  in  Cu 
vessels. 


100  INORGANIC  CHEMISTRY. 

Action  of  Air.— Noble  metals  (An,  Ag,  Pt,  Hg,  Pd,  Rh, 
Eu,  Os,  and  Ir)  do  not  oxidize  on  exposure  to  air;  the  rest  are 
termed  base.  Cu,  Zn,  Al,  and  Sn  do  not  oxidize  in  dry  air.  In 
moist  air  Zn  and  Mg  become  covered  with  a  film  of  oxid  (pre- 
vents further  change);  Cu  with  a  green  deposit  of  basic  car- 
bonate; Pb  with  a  blue-gray  coating  of  carbonate  and  sulphid. 
Iron-rust,  that  forms  in  moist  air  or  H20,  is  a  mixture  of 
Fe2(HO)6  and  Fe203.  Tarnishing  of  silverware  is  due  to  the 
formation  of  Ag2S  by  the  H2S  in  the  air  of  houses;  Cd  turns 
yellow  from  the  same  cause.  Alkali  metals  oxidize  very  quickly, 
and  must  be  kept  in  oily  liquids  (benzene)  that  contain  no  0. 

Action  on  Water.  —  Metals  of  the  alkalies  and  alkaline 
earths  decompose  H20,  sometimes  with  a  colored  flame  of  H, 
and  form  hydroxids: — 

K  +  H20  =  KHO  +  H 

Red-hot  Fe  dipped  into  H20  decomposes  the  steam  that 
is  formed,  setting  H  free  and  producing  the  "blacksmiths' 
scales"  of  Fe304.  Powdered  Mn  also  decomposes  H20.  Pb  is 
slightly  soluble  in  H20,  and  this  solvent  action  is  increased  by 
the  presence  of  chlorids,  nitrates,  and  nitrites,  and  decreased 
by  carbonates  and  sulphates,  which  form  an  insoluble  coating 
on  the  inner  surface  of  the  pipes.  Generally  speaking,  the 
softer  the  water,  the  greater  the  danger  of  Pb  being  dissolved 
by  it.  Sn,  Zn,  Fe,  and  Mg  ppt.  Pb  from  its  solutions. 

Experiment. — Make  a  "lead  tree"  by  dipping  a  strip  of  Zn  into  a 
solution  of  lead  acetate. 

Normal  salts  of  Bi  decompose  on  the  addition  of  much 
H20,  with  ppt.  of  oxysalts  or  subsalts.  Oxids  of  metals  com- 
bine with  H20  to  form  hydroxids  (rarely  acids,  when  there  is 
a  very  large  proportion  of  0),  and  both  oxids  and  hydroxids 
combine  with  acids  to  form  salts. 

Direct  Combination. — All  metals  unite  directly  with  Cl,  F, 
and  0;  most  with  Br,  I,  and  S;  many  with  C  and  P  and  As. 
Freshly  prepared  ferrum  reductum  burns  readily  with  a  red 
glow.  A  strip  of  Zn,  Sn,  or  Fe  ppts.  Pb  or  Bi  from  solutions 
of  their  salts;  a  stick  of  P  or  other  non-metal  collects  crystal- 
line Au  from  a  heated  solution  of  one  of  its  salts;  Zn,  FeS04, 
H2C204,  and  H2S03  also  ppt.  Au.  Hg  dissolves  all  other  metals 
directly  or  indirectly  (Na  amalgam)  except  Fe,  forming  weak 
chemic  compounds  known  as  amalgams. 

Experiment. — Drop  a  globule  of  Hg  into  a  solution  of  AgNO3,  and 
note  formation  of  "arbor  Dianae." 

Experiment. — Make  NH4  amalgam  by  adding  bits  of  Na  to  some 
Hg  in  a  test-tube,  and  pouring  on  the  solution  a  strong  solution  of 


CHEMIC  PROPERTIES  OF  METALS.          101 

NH4C1.     NaCl  and  an  amalgam  result.     The  latter  soon  swells  up  and 
decomposes,  with  the  evolution  of  NH3  and  H,  only  Hg  remaining. 

Pt  sponge  may  be  amalgamated  by  triturating  in  a  warm 
mortar  with  Hg  and  acetic  acid. 

Experiment. — Clean  a  copper  cent  with  HN03,  and  spread  on  a 
globule  of  Hg  to  "silver"  it.  Why  does  it  turn  green  later? 

Molten  cast-iron  dissolves  C,  forming  a  carbid.  The  chief 
impurities  of  cast-iron  are  S,  which  renders  it  brittle  when  hot 
("red-short"),  and  P,  which  renders  it  brittle  when  cold.  Sb 
and  As  unite  readily  with  most  metalloids  and  with  many 
metals,  thus  playing  both  the  +  and  the  —  role.  Both  form 
poisonous  combustible  gases  (H3Sb  and  HsAs)  with  H.  Cu 
on  heating  becomes  coated  with  black  CuO.  Mg  burns  readily 
with  an  intense-white  light  rich  in  actinic  rays.  Zn  is  also 
combustible  at  a  bright-red  heat.  Cd  burns  under  the  blow- 
pipe, leaving  the  brown  oxid.  As  and  Sb  burn  with  a  bluish- 
white  light  and  garlicky  odor;  Te  with  a  blue  flame  tinged 
with  green;  In  with  a  violet  flame.  The  alkaline  and  alkaline 
earthy  metals  also  yield  characteristic  flames  (see  "Pyrology"). 
Ozone  and  H202  corrode  most  metals  by  breaking  up  and  giving 
off  nascent  0. 

Series  of  Salts. — Apt  to  change  spontaneously,  one  into  the 
other. 

Ferrous  and  Ferric. — In  these  two  series  the  metal  is  a 
diad  and  a  triad,  respectively.  In  ferric  compounds  there  are 
always  2  atoms  (or  some  multiple  of  2)  of  Fe  to  each  molecule. 
Theoretically  the  valence  of  Fe  is  4  in  ferric  compounds,  but 
the  two  atoms  combine  with  each  other  so  as  to  lose  one  bond 
of  union  for  other  elements,  as  shown  by  the  graphic  formula 
of  Fe2Cl6:— 


Fe= 


—  Cl 
Cl 

—  Cl 


Fe= 


—  Cl 
Cl 

Cl 


Ferrous  compounds  are  usually  greenish  in  color;  ferric 
salts,  reddish.  They  undergo  spontaneous  change,  one  class 
into  the  otUer,  on  exposure  to  the  air,  as  well  as  by  artificial 
reduction  or  oxidation. 

Experiment. — Convert  FeSO4  into  Fe2(SO4)3  by  heating  a  solution 
of  the  former  with  dilute  HN03,  and  note  corresponding  change  in  color. 


102  INORGANIC  CHEMISTRY. 

Ferrous  salts  can  be  made  by  dissolving  Fe  in  the  corre- 
sponding acid:  ferric  salts,  by  dissolving  Fe203  in  the  acid  of 
the  salt  desired. 

Mercurous  and  Mercuric.  —  In  mercurous  compounds  Hg 
acts  as  a  monad;  in  mercuric,  as  a  diad.  The  ous  salts  are 
probably  unsaturated  as  to  valence,  and  are  prone  to  decom- 
pose into  metallic  Hg  and  the  corresponding  ic  compound.  The 
relation  of  these  two  series  is  readily  seen  by  comparing  the 
graphic  formulas  of  Hg2Cl2  and  HgCl2:  — 


Hg  —  Cl 

Cuprous  and  Cupric.  —  The  ous  and  ic  salts  of  Cu  corre- 
spond in  structure  to  those  of  Hg.  Cuprous  compounds  are 
even  more  unstable  than  mercurous  ones. 

Cobalt  Salts.  —  Hydrated  Co  salts  give  pink  solutions;  an- 
hydrous ones  blue. 

Experiment.  —  Make  sympathetic  ink  by  dissolving  some  Co(N03)2 
in  water.  Write  with  this  'solution  and  a  glass  rod  on  white  paper  and 
let  dry.  The  writing  is  invisible.  Now  dehydrate  by  holding  the  paper 
near  the  flame,  and  the  characters  will  appear  plainly  in  blue. 

Ammonium  Compounds.  —  These  on  exposure  to  the  air 
give  off  the  gas  NH3;  hence  the  term  volatile  alkali  applied 
to  this  metal. 

Experiment.  —  With  moistened  red  litmus-paper,  held  above  the 
open  neck  of  the  bottle,  show  volatility  of  NH4HO,  and  notice  that  the 
red  color  is  restored  on  drying. 

Zinc  salts  are  all  white,  as  are  nearly  all  the  salts  of  the 
alkaline  and  alkaline  earthy  metals. 

Magnesium  salts  are  soluble  in  the  presence  of  ammonium 
compounds,  with  which  they  form  double  salts. 

Protein-silver  compounds,  such  as  protargol,  are  readily 
soluble  in  water,  the  solution  having  marked  antiseptic  prop- 
erties. 

Scale  Compounds.  —  These  are  chiefly  ferric  salts  with  or- 
ganic acids.  They  are  prepared  by  evaporating  to  a  syrupy 
consistence,  pouring  on  plates,  and  peeling  off  when  dry. 
Official  are  ferric  citrate,  ferri  et  ammon.  cit.,  ferri  pyrophos., 
ferri  et  quin.  cit.,  ferri  et  strych.  cit.,  ferri  et  ammon.  tart.,  and 
ferri  et  potassii  tart. 

Actinism.  —  Ag  salts  are  very  susceptible  to  the  action  of 
light,  being  reduced  to  the  black,  finely  divided  metallic  state, 
especially  in  the  presence  of  organic  matter. 


PHYSIOLOGIC  PROPERTIES  OF  METALS.  103 

Experiment. — Show  silvering  of  glass  with  solution  of  Rochelle 
salt,  strong'  AgNO3  solution,  and  enough  NH4HO  to  nearly  dissolve 
precipitate,  warming  carefully. 

Chemic  Corrosion. — Au  is  corroded  by  fused  alkalies  and 
fused  saltpeter,  and  slightly  by  selenic  acid.  Pt  is  corroded 
by  P,  fused  alkalies,  sulphids,  hydroxids,  nitrates,  and  cyanids, 
silica,  and  by  easily  reduced  oxids,  particularly  those  of  Pb. 


PHYSIOLOGIC   PROPERTIES   OF  METALS. 

None  of  the  metals  have  any  distinct  action  on  or  in  the 
body  until  converted  into  compounds  by  the  digestive  juices 
or  otherwise.  Hg  is  most  employed,  either  rubbed  with  chalk 
(gray  powder),  or  with  lard  and  suet  (mercurial  ointment),  or 
with  licorice-powder  and  rose  honey  ("blue  pill").  The  thera- 
peutic alterative  activity  of  these  preparations  is  due  to  Hg20 
formed  by  oxidation  of  the  finely  divided  ("dead  or  extin- 
guished") metal.  Hence  the  better  rubbed  and  the  older,  the 
stronger  they  will  be. 

Salts  of  the  less  positive  metals,  Zn,  Al,  Cu,  Fe  (vegetable 
acid  salts  not  constipating),  and  Pb  (also  sedative)  are  gener- 
ally astringent,  especially  the  sulphates.  Bi  salts  are  soft  and 
insoluble;  hence  used  as  mucous-membrane  sedatives.  Mg 
salts  are  generally  laxative  and  antacid.  Fe  is  an  essential 
element  of  blood-corpuscles,  and  is  therefore  much  used  as  a 
hematmic.  As  is  a  valuable  alterative  and  nerve-tonic.  Liquid 
As  official  preparations  are  of  1-per-cent.  strength;  dose,  2  to 
10  minims.  Many  metallic  salts,  particularly  of  Bi  and  Fe, 
when  taken  internally  blacken  the  stools  by  uniting  with  H2S 
in  the  intestines. 

The  salts  of  the  alkali  metals  are  white  and  solid  and 
mostly  fusible  at  a  red  heat.  Practically  speaking,  all  are  sol- 
uble in  H20,  but  much  less  so  or  not  at  all  in  alcohol.  The 
hydroxids  and  carbonates  are  peculiar  in  not  being  decomposed 
by  heat.  Most  K  salts  are  deliquescent;  most  Na  salts  efflo- 
rescent. K  compounds  are  the  strongest  physiologically  and  the 
most  irritating  and  depressant.  The  stimulating  properties  of 
NH4  compounds  depend  largely,  no  doubt,  on  the  contained  N. 
The  various  salts  of  each  metal  are  usually  prepared  by  treat- 
ing the  most  abundant  and  accessible  compound  with  the  acid 
of  the  salt  desired  or  with  a  solution  of  some  reagent  contain- 
ing the  desired  radical.  The  salts  of  the  alkali  metals  are  the 
most  common  and  useful  mineral  medicines.  They  are  used 
as  cathartics  and  antacids,  and  even  more  as  suitable  vehicles 
for  the  administration  of  medicinal  negative  elements:  e.g., 


104  INORGANIC  CHEMISTRY. 

NaBr  for  Br,  KI  for  I,  etc.    The  alkaline  salts  of  the  vegetable 
acids  are  oxidized  into  carbonates  in  the  system. 

The  common  Ca  compounds  are  essential  to  the  life  and 
growth  of  all  living  beings.  Sr  is  preferred  as  a  base  for  I, 
Br,  and  salicylic  acid,  since  it  is  non-irritant  to  the  stomach. 
Salts  of  the  heavy  metals  generally  are  changed  into  albumin- 
ates  before  absorption  into  the  blood;  hence  are  often  advan- 
tageously given  in  milk.  Caustic  alkalies  act  as  corrosive 
poisons;  large  doses  of  heavy  metals  (except  Fe)  act  as  irri- 
tants mostly.  Most  of  the  heavy  metals  may  give  rise  to 
chronic  poisoning  due  to  medication,,  occupation,  or  environ- 
ments. Hg  and  As  vapors  are  extremely  poisonous.  Metals 
of  the  same  group  vary  in  toxicity  directly  as  their  atomic 
weights. 

USES   OF  METALS. 

The  most  important  of  the  industrial  metals  are  Fe,  Al, 
Cu,  Zn,  Sn,  and  Pb.  Fe  is  the  most  useful  metal,  and  is  em- 
ployed in  innumerable  ways.  So  necessary  has  it  been  to  the 
progress  of  the  race  that  the  historic  period  of  the  earth  is 
often  styled  the  iron  age.  Wrought  or  bar  Fe  is  of  special  use 
for  building  purposes  and  Bessemer  steel;  white  cast  Fe  for 
forging,  puddling,  and  steel;  cement  steel  for  armor  plates; 
carbon  or  crucible  steel  for  springs,  tools,  and  firearms;  open- 
hearth  or  low-carbon  steel  for  tires,  tanks,  fire-boxes,  etc.;  and 
Bessemer  steel  for  rails  and  construction  material. 

The  metal  Al  is  the  best  suited  of  all  metals  for  culinary 
vessels,  on  account  of  its  lightness  and  because  it  does  not 
tarnish  nor  is  acted  on  by  vegetable  acids  so  much  as  Zn,  Sn, 
and  Cu  are;  it  is,  moreover,  not  at  all  poisonous.  Al  is  also 
employed  for  covering  roofs  and  monuments,  for  ornamental 
purposes,  and  in  dental  plates,  and  is  sometimes  used  with  S 
in  vulcanizing  rubber. 

Zn  is  used  in  the  manufacture  of  brass,  desilvering  Pb,  in 
dental  dies,  electric  batteries,  and  for  coating  or  "galvanizing" 
sheet  iron  for  roofing,  pails,  tubs,  etc.  The  Fe  is  cleansed  in 
dilute  H2S04  and  then  dipped  into  molten  Zn. 

Cu  is  utilized  for  money,  electric  wires,  cartridges,  various 
utensils,  in  sheathing  ships,  and  to  give  a  ruby  color  to  glass. 
Its  alloys  are  of  extensive  service. 

Tin  plate  consists  of  sheet  Fe  coated  with  Sn;  if  the  coat- 
ing is  thick,  it  is  styled  block  tin.  Pins  are  made  of  brass  wire 
covered  with  tin  amalgam.  Tin-foil  is  made  of  Pb  between 
thin  strips  of  Sn.  In  much  of  the  ordinary  tinware  the  coating 


USES  OF  METALS.  105 

of  Sn  is  adulterated  with  Pb,  and  rusts  more  quickly  than  it 
should.  Pure  tin-foil  is  sometimes  used  as  a  dental  filling.  The 
insoluble  Sn02  formed  between  the  wall  and  the  filling  acts 
as  a  preservative.  Powdered  Sn  has  been  administered  to  pro- 
mote the  expulsion  of  worms. 

Pb  is  used  very  extensively  in  the  manufacture  of  shot, 
bullets,  water-pipes,  chemic  vessels,  dental  counter-dies,  and 
various  alloys,  notably  solder  and  type-metal.  Cylinders  of 
Pb  have  been  used  for  filling  the  root-canals  of  teeth. 

Of  secondary  importance  in  manufacture  are  Mn,  Cr,  Ni, 
Co,  As,  Bi,  and  Sb.  The  chief  use  of  Mn  is  in  making  ferro- 
manganese  for  the  Bessemer  steel  process.  Cr  is  used  in  the 
proportion  of  0.5  to  0.75  per  cent,  to  harden  steel.  Ni  is 
utilized  as  an  anti-rust  plating  for  steel  and  Fe  instruments 
and  in  armor-plate.  The  principal  use  of  Co  is  in  making  the 
blue  pigment  smalt,  by  fusing  some  salt  of  this  metal  with 
finely-powdered  glass.  As  (1/2  per  cent.)  gives  the  round  shape 
to  bullets.  A  mixture  of  Co  ("glance")  and  As  is  used  as  fly- 
stone  and  black  fly-paper.  As  is  also  used  in  fire-works.  Bi 
is  employed  largely  in  fusible  alloys  (safety-plugs),  in  dies  for 
wood-cut  and  stereotype  impressions,  and  in  dental  dies  and 
counter-dies.  Sb  is  used  in  type-metal  because  it  expands  on 
cooling,  and  in  various  other  alloys.  U  salts  color  glass  and 
render  it  fluorescent. 

Mg  is  of  service  in  photographing  objects  in  dark  places; 
also  for  flash-lights  and  signaling,  in  the  Bengal  fires  and 
pyrotechnics.  It  is  sometimes  substituted  for  Zn  in  Marsh's 
test. 

K  and  ISTa,  on  account  of  their  strong  attraction  for  nega- 
tive elements,  have  been  used  in  the  separation  from  their  ores 
of  other  metals,  particularly  Mg,  Al,  B,  and  Si.  Na  is  a  com- 
mon laboratory  reducing  agent.  Na  amalgam  is  often  em- 
ployed in  place  of  the  single  metal. 

On  account  of  its  density  and  wide  range  of  fluidity,  Hg 
is  much  used  in  making  thermometers,  barometers,  and  other 
scientific  instruments.  Its  avidity  for  Au  accounts  for  its  use 
in  placer  mining.  An  amalgam  of  Sn  and  Hg  is  used  for  coat- 
ing the  backs  of  mirrors. 

The  value  of  the  precious  metals  Au,  Pt,  and  Ag  depends 
partly  on  their  comparative  rarity  and  partly  on  the  fact  that 
they  do  not  readily  fuse  or  oxidize.  Ag  is  made  use  of  widely 
in  the  manufacture  of  surgical  instruments  and  sutures,  being 
itself  slightly  antiseptic.  It  is  further  used  for  certain  chemic 
apparatus,  for  coins,  electroplating,  the  silvering  of  glass  for 
mirrors,  and  as  the  source  of  Ag  salts.  Ag  coins  are  alloyed 


106  INORGANIC  CHEMISTRY. 

with  10  per  cent,  of  Cu  to  give  the  needed  hardness.  The 
silver  electroplating  solution  consists  of  1  part  of  AgN03  in  50 
ILO,  combined  with  5  KCN  in  20  H20;  the  AgCN  thus  formed, 
though  insoluble  in  H20,  is  soluble  in  the  excess  of  alkaline 
cyanid.  The  Ag  bar  attached  to  the  +  P°le  is  gradually  dis- 
solved by  the  CN"  liberated  at  the  same  pole,  keeping  the  pro- 
portion of  AgCIST  in  the  solution  about  constant.  Ag  is  the 
most  essential  ingredient  of  a  good  amalgam  alloy  for  filling 
teeth.  Electrolysis  of  Ag  in  AgCN  is  practiced  for  making  base 
plates  for  artificial  teeth. 

Au  is  used  as  coin  and  for  jewelry,  on  account  of  its  soft- 
ness being  alloyed  with  Ag  and  Cu.  The  fineness  of  Au  is 
represented  in  carats,  the  pure  metal  being  designated  24  c. 
fine.  United  States  gold  coins  are  21.6  c.  fine;  jewelry  usually 
14  c.  Gilding  is  performed  by  means  of  electrolysis  of  a  solu- 
tion containing  AuCl3  and  KCN.  Glass  and  porcelain  are 
decorated  in  the  same  manner  or  with  the  purple  of  Cassius 
(made  by  reaction  between  AuCl3  and  SnCl2).  Gold  salts  are 
used  in  photography  for  fixing  and  toning.  The  gold  leaf  used 
by  dentists  and  sign-painters  is  prepared  by  passing  Au  between 
rollers  till  about  V300  inch  thick,  then  hammering  between 
calf-skin  vellum  till  1/16000o  to  1/200poo  of- an  inch  in  thickness. 
The  cohesive  Au  used  for  dental  fillings  is  prepared  by  heating 
gold-foil  to  redness,  thus  restoring  the  cohesive  properties  lost 
by  beating,  and  driving  off  moisture  and  gases  from  the  sur- 
face. Dentists  generally  employ  gold  plate  of  18  to  20  c.  fine- 
ness, the  remaining  4  or  6  c.  being  made  up  of  from  two  to 
six  times  more  Ag  than  Cu.  If  a  higher  carat  is  desired  for 
greater  tenacity  (clasps  and  wires),  a  little  Pt  is  added,  and  the 
Cu  exceeds  the  Ag.  Gold  plates  should  be  "pickled"  in  dilute 
HN~0:{  after  swaging,  in  order  to  remove  every  particle  of  die 
metal. 

On  account  of  its  high  m.p.,  Pt  is  much  employed  for 
crucibles,  evaporating  dishes,  stills  (H2S04),  flame-test  wires, 
and  in  electric  apparatus.  An  alloy  with  Ir  is  harder,  less 
fusible,  and  less  subject  to  chemic  action  than  is  the  pure 
metal.  Pt  is  used  to  some  extent  for  ornamenting  porcelain. 
It  is  also  employed  in  dentistry  for  pins  for  artificial  teeth,  for 
continuous  gum-plates,  and  when  finely  powdered  for  coloring 
artificial  teeth. 

The  rare  metals  are  mainly  of  theoretic  interest.  Pd  is 
used  for  mounting  scientific  instruments  and  plating  silver 
goods.  It  is  non-magnetic  and  its  elasticity  is  not  affected  by 
changes  in  temperature,  hence  it  is  used  in  the  hair-springs 
of  watches.  Va  gives  a  gloss  to  satin,  and  is  used  to  set  black 


ALLOYS  IN  GENERAL.  107 

in  fabrics.     Tungsten  or  wolfram  is  used  in  the  manufacture 
of  Welsbach  mantles  for  gas-burners. 


METALLIC    GROUPS. 

Alkali  Metals.— This  includes  K,  Na,  Li,  NH4,  Rb,  and 
Cs.  The  group  is  so  called  because  the  oxids,  hydrates,  car- 
bonates, and  some  phosphates  of  the  metals  composing  it  are 
of  an  alkaline  reaction.  All  are  univalent,  and  the  first  three 
are  lighter  than  H20,  which  they  deoxidize,  forming  hydrates 
and  setting  free  H.  They  are  soft,  silver-white,  easily  fusible, 
and  volatilize  at  high  temperatures.  They  are  strongly  posi- 
tive; hence  have  a  great  affinity  for  negative  elements.  Their 
salts  are  all  practically  soluble,  and  increase  in  physiologic 
potency  with  the  atomic  weights  of  the  metals. 

Metals  of  Alkaline  Earths.— These  include  Ca,  Ba,  and  Sr, 
and  (for  present  convenience)  Mg.  They  are  all  diads.  They 
burn  readily  and  decompose  H20  at  high  temperatures.  HC1 
and  dilute  H2S04  dissolve  them.  Their  halogen  salts  are 
freely — their  sulphates,  oxids,  and  hydrates  slightly  (except 
MgSOJ — soluble  in  H20;  carbonates,  phosphates,  and  borates 
insoluble. 

Lead  Group. — This  comprises  Pb,  Cu,  Bi,  Ag,  Hg,  and  Cd. 
These  metals  are  soft  and  heavy.  Their  sulphids  are  black  and 
insoluble  in  H20,  dilute  acids,  and  NH4HS;  their  halogen  salts 
slightly,  if  at  all,  soluble.  The  carbonate  and  sulphate  of  Pb 
are  also  insoluble. 

Aluminum  Group.  —  Al,  In,  Ga.  These  are  practically 
trivalent.  Their  double  sulphates  are  called  alums.  Their 
oxids  are  insoluble. 

Iron  Group. — Fe,  Mn,  Co,  Ni,  Or,  Zn.  These  are  divalent 
or  trivalent  and  more  or  less  magnetic.  Their  sulphids  are 
soluble  in  dilute  acids. 

Arsenic  Group. — As,  Sb,  Sn,  Au,  Pt,  Mo.  Their  sulphids 
are  insoluble  in  dilute  acids;  soluble  in  NH4HS. 


ALLOYS   IN   GENERAL. 

A  combination  of  metals  fused  together  is  termed  an 
alloy;  a  solution  of  a  single  metal  in  Hg,  an  amalgam;  a  solu- 
tion of  an  alloy  in  Hg,  an  amalgam-alloy.  Some  of  them  are 
probably  feeble  chemic  compounds,  forming  crystals,  but  most 
appear  to  be  mechanic  mixtures  or  solutions.  In  preparing 
alloys  the  least  fusible  metal  should  be  melted  first,  and  the 


108  INORGANIC  CHEMISTRY. 

next  least  fusible  added  little  by  little  with  constant  stirring, 
preventing  oxidation  with  borax  or  charcoal,  and  reducing  the 
heat  gradually  according  to  the  fusibility  of  the  metal  next 
added. 

Alloys  generally  have  a  lower  fusing-point  than  the  mean 
of  their  constituents;  sometimes  lower  than  any  single  con- 
stituent. Alloys  of  Pb,  Sn,  Hg,  Cd,  and  Bi  are  noted  for  their 
fusibility.  Wood's  fusible  metal  melts  at  68°;  Eose's  metal  at 
94°;  stereotyping  metal  melts  in  boiling  H20.  An  alloy  of 
K  and  Na  is  liquid  at  ordinary  temperatures.  Fusible  alloys 
are  useful  in  dovetailing  teeth  into  old  rubber  and  celluloid 
plates  with  the  aid  of  a  warm  burnisher.  Fluxes  are  substances 
added  to  ores  to  aid  in  reduction  by  lowering  the  m.p.  in  this 
way. 

Alloys  are  usually  harder  than  the  hardest  metal  com- 
posing them.  Even  the  addition  of  such  soft  metals  as  Sn  and 
Pb  generally  hardens  other  metals.  Cu  is  added  to  Ag  and  Au 
for  this  reason.  The  alloy  iridosmine,  on  account  of  its  hard- 
ness, is  used  to  tip  ("diamond  points")  gold  pens,  the  particles 
being  pushed  into  the  point  of  the  pen  while  cold.  Al  bronze 
is  employed  for  castings,  and  is  added  to  steel,  Zn,  and  Ag  to 
improve  these  metals  in  hardness  and  tenacity.  Phosphor- 
iridium,  made  by  heating  these  two  elements  together,  has 
great  power  of  retaining  lubricants.  An  alloy  with  50  per  cent, 
of  Fe  is  not  scratched  by  the  best  file. 

The  tenacity  of  metals  is  sometimes  diminished,  but  fre- 
quently increased,  by  alloying,  as  illustrated  by  Al  bronze. 
Steel  is  2  */2  times  as  tenacious  as  iron.  The  addition  of  12 
per  cent,  of  Sn  to  Cu  trebles  the  tenacity  of  the  latter.  Sb 
and  As,  however,  render  alloys  brittle,  and  even  a  trace  of  Pb 
makes  Au  much  less  ductile  and  malleable. 

The  color  of  .alloys  is  commonly  gray,  but  is  sometimes 
superior  to  that  of  their  constituents.  Thus,  brass  has  a  better 
hue  than  Cu,  is  less  subject  to  atmospheric  action,  and  is  more 
easily  worked  in  the  lathe.  Al  bronze  resembles  Au.  Equal 
parts  of  Sb  and  Cu  fused  together  yield  a  violet  alloy.  Metallic 
luster  is  often  modified  or  even  destroyed  by  alloying.  This 
is  particularly  true  of  Au. 

The  sp.  gr.  of  alloys  nearly  always  varies  from  the  average 
of  their  constituents.  An  alloy  of  Ag  and  Au  is  below — one  of 
Pb  and  Sn  above — the  mean  of  its  constituents. 

Liquation  is  the  term  applied  to  the  gravity  phenomena 
whereby  the  metals  composing  an  alloy  form  separate  layers 
when  the  molten  mixture  is  allowed  to  cool  slowly.  Pb  and 
Zn,  or  Pb  and  Ag,  or  Cu  and  Ag  can  be  parted  in  this  way. 


ALLOYS  IN  GENERAL. 
COMMON  ALLOYS. 


109 


NAME. 

PARTS  IN  100. 

d 

SILVER. 

COPPER. 

fc 
H 

g 
N 

G 

•< 
• 
d 

ALUMINUM. 

NICKEL. 

ANTIMONY. 

BISMUTH. 

MEKCURT. 

SPELTER. 

CADMIUM. 

1 

MANGANESE. 

i  PHOSPHORUS. 

U.  S.  Gold  Coins  .  . 
U.  S.  Silver  Coins  . 
Green  Gold  .... 
Red  Gold  
Niirnberg  Gold  .  . 

90 

75 
75 
2.5 

90 
25 

10 
10 

25 
90 

84  5 

15.5 
20 
33.3 
6 

5 

1 

7.5 
10 

20 

20 
25 

1 

German  Silver  .  . 

60 
66.6 
91 
90 
75 
90 
80 
90 
88  ' 
9 
1.84 
85 

2 

Aluminum  Bronze 
Manganese  Bronze 
Phosphor-bronze    . 
Bell-metal 

9 
20 
10 

73 
81.9 
15 

80 

12.5 

75 

2 

10 

2.5 

18 
16.25 

Gun-metal  .... 
Hercules  Metnl  .  . 
Babbitt-metal  .  .  . 
Britannia  
Pinchbeck 

20 

Pewter  

16  5 

67 

16.5 

50 

50 

4 

20 
31 

80 
12  5 

19 
25 

Fusible  Alloy 

Rose's  Metal  .  .  . 
Soft  Solder  .... 
Plumber's  Solder  . 

I>ental  Solder 

•   • 

25 
60 
33.3 
45 

25 
40 
66.6 

!  -H 

•   • 

50 

10 

40 

401-   - 

20 

Brass  Solder  .  .  . 
Silver  Solder  .  .  . 

73 
9 

75" 
9 
4 
4 

25 
18 

Gold  Solder  .... 
Aluminum  Solder  . 

83 

90 

r 

6 

Bronze.    a  Brass. 


110  INORGANIC  CHEMISTRY. 

When  metals  differ  greatly  in  fusibility  it  is  best  to  unite  first 
those  that  combine  most  readily. 

The  property  of  sonorousness,  in  which  most  single  metals 
are  deficient,  is  much  enhanced  by  alloying.  Examples  are 
bell-metal  and  an  alloy  of  Cu  and  Al. 

Elasticity  may  sometimes  be  increased  by  adding  a  small 
proportion  of  other  metals.  "Spring  gold"  contains  a  small 
percentage  of  Pt. 

Alloys  of  Zn  or  Hg  and  other  metals  are  accompanied  by 
heat.  The  specific  heat  of  an  alloy  is  the  mean  of  the  specific 
heat  of  the  component  metals.  Conducting-power  for  heat  and 
electricity  is  generally  reduced  in  alloys.  The  coefficient  of 
heat-expansion  in  alloys  is  usually  about  the  average  of  their 
ingredients.  An  exception  is  copper-tin  alloy,  which  expands 
less  than  pure  Cu,  although  Sn  alone  expands  more  than  Cu. 

The  solubility  of  alloyed  metals  is  often  considerably 
altered.  Thus,  Ag  becomes  insoluble  in  HN03  when  alloyed 
with  more  than  25  per  cent,  of  Au,  and  Pt  becomes  quite  sol- 
uble in  HN03  when  alloyed  with  Au  or  with  ten  times  as  much 
Ag.  Alloys  of  Sn  and  Pb  and  the  tin-silver  amalgam-alloys 
used  for  filling  teeth  are  readily  tarnished  or  oxidized. 

Experiment. — Dissolve  a  10-cent  piece  in  HNO3.  What  color  is 
produced,  and  why? 

Dental  amalgam-alloys,  used  for  fillings,  are  usually  com- 
posed of  65  (40)  parts  Ag  and  35  (60)  parts  Sn.  This  type  may 
be  modified  by  the  addition  of  a  few  per -cent,  of  spongy  Pt, 
Cu,  Au,  Zn,  Pd,  Al,  Sb  Fe,  or  Cd.  The  advantages  of  an 
amalgam-alloy  over  a  simple  amalgam  are  that  opposite  prop- 
erties— for  instance,  expansion  and  contraction — may  neutral- 
ize each  other,  and  also  help  to  set  more  quickly.  An  amalgam 
may  be  prepared  (1)  by  bringing  the  metal  or  alloy  in  contact 
with  Hg;  (2)  by  adding  Hg  to  the  molten  alloy;  (3)  by  action 
of  the  metal  on  a  salt  of  Hg;  (4)  by  action  of  Hg  on  a  salt  of 
the  metal.  The  third  method  is  illustrated  when  metallic  in- 
struments are  immersed  in  HgCl2  solution.  The  time  of  setting 
varies  from  hours  to  days,  according  to  the  ingredients  and 
whether  the  excess  of  Hg  has  been  squeezed  out  or  not,  using 
chamois  or  good  muslin. 

Discoloration  of  amalgam  fillings  is  due  to  H2S  from  de- 
composing food  in  the  mouth.  Ag,  Cu,  and  Pd  are  blackened; 
Cd  turned  yellow.  The  Ag2S  thus  formed  is  antiseptic,  serving 
to  preserve  the  teeth.  The  discoloration  of  gold  fillings  is  said 
to  be  due  to  oxidation  of  the  steel  worn  from  pluggers.  Gal- 
vanic action  between  the  ingredients  of  fillings  may  also  have 


ALLOYS  IN  GENERAL.  HI 

something  to  do  with  their  discoloration  and  disintegration, 
especially  when  Cu  is  present.  Cu  amalgams  waste,  because  the 
black  oxid  and  sulphid  on  the  surface  change  to  the  soluble 
sulphate.  Al  amalgam  in  the  presence  of  moisture  swells  up 
and  decomposes  into  A1203  and  Hg,  with  production  of  heat. 

The  black  "dirt"  that  is  given  off  in  mixing  ordinary 
amalgam-alloy  is  a  lower  oxid  of  Sn,  and  is  more  abundant 
after  annealing.  Pressure  on  solid  amalgams  causes  a  yielding 
or  flow,  which  varies  with  the  amount  of  stress.  "Electric 
amalgam"  is  commonly  prepared  with  1  part  each  of  Sn  and 
Zn  and  3  parts  Hg. 

Dental  solders  are  special  alloys  for  joining  metallic  sur- 
faces. They  usually  consist  of  the  metal  to  be  soldered,  with 
another  to  lower  the  fusing-point.  Hard  solders  fuse  at  or 
above  red  heat;  soft  solders  below  this  point.  By  autogenous 
soldering  is  meant  the  fusing  together  of  contiguous  parts  of 
the  same  metal,  usually  Pb  or  Pt.  Soft  solders  are  used  in  the 
stick  form;  hard  solders  in  ingot  filings;  Au  and  Ag  solders 
as  clippings  from  rolled  sheets.  They  are  prepared  in  a  crucible 
in  the  same  manner  as  other  alloys. 

The  best  tin  solder  for  dental  use  contains  1  Pb  and  2  Sn, 
and  melts  at  171°.  Bi  solders  are  composed  of  Bi,  Sn,  and 
Pb,  and  melt  at  from  95°  to  160°.  Eeally  good  Al  solders  are 
not  to  be  had  at  present.  As  a  dental  solder  Hall  recommends 
a  combination  of  45  parts  each  of  Al  and  Sn  and  10  parts  Hg, 
the  solder  being  applied  with  a  brazing  blow-pipe  and  a  piece 
of  steel  wire.  Fused  AgCl  is  used  as  a  flux.  Al  bronze  is  readily 
soldered  with  alloys  of  Au,  Ag,  and  Cu. 

Brass  solder  is  hard,  and  varies  from  yellow  to  white  ac- 
cording to  the  amount  of  Sn.  Silver  solders  consist  of  Ag 
alloyed  with  Cu,  Zn,  and  Sn,  and  are  used  in  soldering  Ag, 
German  silver,  brass,  cast-iron,  and  steel.  For  general  use  an 
alloy  of  8  Ag,  1  Cu,  and  2  Zn  is  recommended.  For  soldering 
steel  3  parts  Ag  and  1  part  Cu  is  mentioned  by  Brannt. 

Gold  solders  range  from  12  to  20  c.  in  fineness,  the  re- 
mainder being  made  up  of  Ag  and  brass  in  nearly  equal  pro- 
portions. For  crown  and  bridge  work  Essig  commends  a  solder 
containing  20  Au,  2  Ag,  and  1  each  Cu  and  spelter  (equal  parts 
Cu  and  Zn). 

Soft  solders  are  generally  applied  with  a  clean  and  tinned 
Cu  bit.  A  brazing  blow-pipe  is  used  for  hard  solders.  The 
surfaces  to  be  united  are  commonly  "pickled"  in  dilute  HC1 
or  H2S04.  Rosins  or  soldering  fluids.,  such  as  a  saturated  solu- 
tion of  Zn  in  HC1,  are  employed  with  soft  solders  as  protective 
fluxes.  A  thin  paste  of  borax  and  H20  is  used,  as  a  rule,  with 


112 


INORGANIC  CHEMISTRY. 


hard  solders.    The  oxidizing  flame  should  be  avoided  in  solder- 
ing. 

Dental  dies  are  made  of  Zn  or  babbitt-metal  (1  Cu,  2  Sb, 
and  8  Sn),  Spence's  metal  (FeS  melted  in  S),  or  type-metal 
(1  Sb,  1  Sn,  and  4  Pb).  Alloys  for  counter-dies  usually  consist 
of  1  part  Sn  and  7  parts  Pb. 


Fig.  21. — Apparatus  for  Determining  the  Melting-point  of  a  Solid. 


Experiment  to  Determine  the  Melting-point  of  a  Fusible  Alloy.— 
Place  alloy  in  a  test-tube,  to  which  is  bound  a  thermometer,  and  im- 
merse both  in  a  beaker  of  H,0.  Heat  the  H20,  with  constant  agitation 
over  a  hot  plate,  till  the  alloy  melts.  Then  let  cool  and  note  tempera- 
ture at  which  the  alloy  solidifies.  If  the  alloy  does  not  fuse  at  or  below 
the  b.p.  of  H2O,  raise  this  point  by  saturating  with  NaCl  or  NH4C1  or 
by  using  some  liquid  (glycerin  or  H2S04)  with  a  higher  b.p.  than  H20. 


HYDROGEN.  113 


METALLOIDS. 

These  elements  differ  from  the  metals  by  taking  generally 
the  electronegative  role.  Their  oxids  are  acid  in  reaction. 
Some  of  them  are  gases,  one  (Br)  a  liquid,  and  a  number  solids. 


HYDROGEN. 

Though,  strictly  speaking,  a  gaseous  metal,  H  will,  for  con- 
venience, be  considered  with  the  metalloids.  The  element  is 
so  called  because,  in  connection  with  0,  it  forms  water.  It 
was  first  observed  by  Paracelsus  in  the  sixteenth  century.  It 
was  carefully  investigated  by  Cavendish  in  1766,  who  termed 
it  inflammable  air,  and  later  demonstrated  that  it  formed  H20 
with  half  its  volume  of  0. 

H  occurs  free  in  Nature  in  small  quantities,  occluded  in 
meteorites,  in  carnallite,  and  in  volcanic  and  other  natural 
gases.  It  is  one  of  the  products  of  decomposition  of  organic 
substances,  and  hence  is  found  in  the  lungs,  stomach,  and  in- 
testines, and  in  sewer-gas.  It  is  believed  to  be  the  chief  con- 
stituent of  the  solar  atmosphere.  The  compounds  of  II  with 
other  elements  are  very  numerous  and  important,  including 
water,  ammonia,  marsh-gas,  all  acids  and  acid  salts,  hydrates, 
and  most  fuels  and  substances  used  for  lighting,  as  well  as 
sugars,  starches,  and  hydrocarbons. 

It  may  be  prepared  from  H20  by  electrolysis  or  by  the 
action  of  metals  (Na,  for  example)  that  have  a  great  affinity 
for  0.  The  usual  method  of  production  is  by  treating  granules, 
of  Zn  with  diluted  (1  to  5)  H2S04  or  HC1:— 


Zn  +  H2S04  +  H20  =  ZnS04  +  H20  +  H 


It  is  collected  by  displacement  over  water.  The  process 
of  evolution  is  hastened  if  an  inert,  more  electronegative  sub- 
stance, such  as  Cu  or  PtCl4,  is  immersed  in  the  fluid.  H  is  also 
evolved  on  heating  certain  metals  (Zn,  Mg,  and  Al)  with  strong 
solutions  of  alkaline  hydrates. 

H  is  a  colorless,  odorless,  tasteless  gas.  It  is  the  lightest 
substance  known;  hence  is  taken  as  the  unit  of  atomic  weight 
and  density.  Air  is  nearly  15  times  as  heavy.  A  liter  of  H 
at  0°  and  760  mm.  pressure  weighs  a  crith:  equivalent  to 
0.0896  gm.  H  is  the  most  difficult  of  gases  to  liquefy,  having 
been  condensed  by  Dewar  in  1898  to  a  steel-blue  liquid  under 
a  pressure  of  600  atmospheres  at  —  140°.  This  liquid  is  the 
lightest  known  (sp.  gr.,  0.07)  and  boils  at  —238°.  H  is  the 


114  INORGANIC  CHEMISTRY. 

most  diffusible  of  gases,  has  the  greatest  specific  heat  (3.4),  is 
the  most  refractive  of  gases,  and  the  best  gaseous  conductor 
of  heat  and  electricity.  One  volume  of  the  gas  dissolves  in  50 
of  water.  It  is  readily  absorbed  or  occluded  by  a  number  of 
metals,  particularly  Pt  and  Pd  (forming  an  alloy),  the  latter 
metal  taking  up  400  volumes  of  the  gas,  and  the  former  (in 
the  finely  divided  or  spongy  state)  has  so  great  an  avidity  for 
this  gas  as  to  ignite  it  through  the  heat  produced  by  its  rapid 
absorption. 

Experiment. — Make  H  and  pass  gas  on  to  a  disk  of  spongy  Pt  till 
ignition  takes  place. 

In  its  chemic  relations  H  generally  plays  the  positive  role, 
especially  in  acids,  and  is  displaced  from  its  combinations  by 


Fig.  22.— Preparation  of  Hydrogen. 

metals  which  are  more  electropositive.  H  is  not  a  supporter 
of  combustion,  and  at  ordinary  temperatures  has  little  affinity 
for  0,  but  is  quite  combustible  at  elevated  temperatures,  burn- 
ing with  a  pale-blue  flame  and  forming  H20;  when  mixed  with 
air  or  0,  it  explodes  with  violence.  On  account  of  its  avidity 
for  0  and  other  non-metals,  heated  H  is  a  powerful  reducing 
agent.  Nascent  H  unites  with  solutions  of  As  and  Sb  to  form 
inflammable  gaseous  compounds. 

H  gas  is  neither  noxious  nor  beneficial  physiologically.  It 
can  be  inhaled  for  a  short  time  without  injury,  producing  only 
a  peculiar  change  in  the  voice:  i.e.,  a  higher  pitch,  due  to  more 
rapid  vibration  of  vocal  cords  in  rarer  atmosphere. 


HALOGENS.  115 

Experiment.  —  Make  H  and  show  properties  of  combustibility,  but 
not  supporting  combustion,  levity,  and  diffusibility.  Take  care  to  expel 
all  air  from  iiask  before  igniting. 

Test.  —  O  +  H2  =  H2O,  shown  by  holding  cool  glass  vessel  near 
burning  jet. 

Combined  with  0  by  means  of  the  oxyhydrogen  blow-pipe, 
it  yields  a  very  intense  heat,  sometimes  used  for  fusion  and 
reduction  purposes.  Reduced  iron,  or  Fe  by  H,  is  prepared  in 
this  manner.  H  was  formerly  utilized  for  balloons,  having  a 
lifting  power  of  a  little  more  than  one  ounce  to  the  cubic  foot, 
but  has  proved  too  diffusible  to  be  of  much  service  in  this  con- 
nection. 

HELIUM. 

This  gaseous  element  was  first  discovered  in  the  solar 
atmosphere  by  means  of  the  spectroscope,  in  which  it  shows 
a  yellow  line  at  D  3.  Recently  it  has  been  shown  to  be  oc- 
cluded in  many  minerals,  often  accompanied  by  H,  and  is  also 
present  in  the  gases  of  certain  springs  and  to  a  very  slight 
extent  in  the  air.  It  is  a  very  inert  substance,  and  extremely 
difficult  to  liquefy. 

HALOGENS. 

This  group  is  so  called  because  most  of  its  members  can 
be  derived  from  sea-water  and  plants.  Its  members  form 
binary  salts  by  combining  directly  with  metals.  It  includes 
four  elements,  two  of  which,  Cl  and  F,  are  gases;  Br,  a  liquid; 
and  I,  a  solid.  All  are  strongly  electronegative,  neutral,  and 
generally  univalent.  They  have  a  sharp,  acrid  taste,  and  a 
characteristic  irritating  odor;  they  corrode  metals,  combine 
with  H  to  form  colorless  acid  gases,  and  act  as  bleaching  and 
disinfecting  agents.  Their  relative  combining  energy  is  in- 
versely to  their  atomic  weights.  They  can  all  be  prepared 
(except  F)  by  removing  H  from  their  acids  by  means  of  0 
derived  from  Mn0. 


2. 


Experiment.  —  Drop  a  few  grains  of  MnO,  into  three  test-tubes. 
Then  add  to  the  first  a  little  powdered  NaCl,  to  the  second  NaBr,  and 
to  the  third  KI.  Next  pour  into  each  a  few  drops  of  H2SO4  and  warm. 
Note  formation  of  Cl  in  the  first  tube,  Br  in  the  second,  and  I  in  the 
third. 

Fluorin.  —  F  was  first  isolated  with  electricity  by  Moissan 
in  1886.  Its  name  is  derived  from  the  principal  natural  com- 
pound, fluorspar,  CaF2. 

This  element  occurs  very  sparingly  in  a  free  state,  but  as 
CaF2  it  is  found  nearly  everywhere.  Cryolite  (N"aFAl2F6)  is 


116 


INORGANIC  CHEMISTRY. 


a  porous  rock  abundant  in  Greenland.    F  is  also  present  in  sea 
and  mineral  waters,  bones,  teeth,  and  milk. 

F  is  a  colorless  gas,  so  powerful  in  its  affinities  for  other 
substances  that  it  can  be  prepared  only  by  electrolysis  of  HF 
in  vessels  of  Pt  or  CaF2.  It  is  the  only  element  that  does  not 
combine  with  0. 


Fig.  23.— Preparation  of  Chlorin. 


Chlorin. — This  element  was  first  prepared  by  Scheele  in 
1774,  and  was  so  named  by  Davy  because  of  its  greenish  color. 
Cl  never  occurs  free  in  Nature,  but  in  combination  with  other 
elements  it  is  of  almost  universal  distribution. 

For  laboratory  or  medical  use  it  is  usually  prepared  in  one 
of  the  two  ways  indicated  by  the  following  equations: — 


HALOGENS.  117 

Mn02  +  4HC1  =  2H20  +  MnCl2  +  C12  (U.  S.  P.  method) 
CaCl20  +  2HC1  =  C12  +  CaCl2  +  H20 

It  will  be  noted  in  both  instances  that  the  H  of  HC1  is 
oxidized  and  Cl  set  free. 

Experiment. — Make  and  collect  the  gas  dry  (by  downward  dis- 
placement) and  in  tLO. 

Cl  is  a  greenish-yellow  gas  of  a  peculiar,  penetrating,  suf- 
focating odor  and  acid,  astringent  taste.  It  is  2  1/2  times  as 
heavy  as  air,  and  can  be  condensed  to  an  oily  liquid  by  4  atmos- 
pheres at  ordinary  temperatures.  One  volume  of  water  absorbs 
nearly  3  volumes  of  the  gas.  Aqua  chlori,  thus  obtained,  should 
contain  not  less  than  0.4  per  cent.,  by  weight,  of  Cl.  Cl  water 
should  be  protected  from  air  and  light,  as  otherwise  it  changes 
to  HC1. 

Cl  is  highly  electronegative;  hence  has  affinity  for  most 
other  elements,  especially  H  and  other  metals.  The  gas  pre- 
pared in  daylight  is  much  more  active  than  that  made  in  the 
dark. 

Experiment. — Mix  equal  volumes  of  H  and  Cl  in  a  flask,  and  show 
that  the  color  disappears  with  chemic  combination  and  that  the  volume 
of  the  HC1  formed  equals  that  of  both  gases. 

Experiment.  —  Fill  one  test-tube  with  H  and  another  with  Cl. 
Place  mouths  of  tubes  together  (Cl  above)  and  hold  in  sunlight  or  near 
a  flame.  An  explosion  results. 

H  burns  freely  in  Cl  and  Cl  in  H.  This  fact  may  be  shown 
by  holding  a  candle  in  a  jar  of  Cl;  the  C  of  the  candle  is  un- 
burned  and  produces  a  dense  cloud  of  smoke. 

Experiment. — Throw  a  piece  of  paper  wet  with  warm  turpentine 
(C10H1G)  into  Cl.  Explain  spontaneous  combustion  and  dense  smoke. 

Experiment. — Show  affinity  of  Cl  for  Sb  by  dropping  some  finely 
powdered  Sb  into  a  jar  of  the  gas.  It  burns  and  is  converted  into  a 
white  powder:  SbCl3. 

On  account  of  its  affinity  for  H,  Cl  acts  as  a  bleacher  (for 
cotton,  linen,  paper,  and  discolored  teeth),  deodorizer,  and  dis- 
infectant: i.e.,  freshly  generated  Cl  unites  with  the  H  of  H20 
and  sets  free  nascent  0,  which  is  the  really  active  agent  in 
destroying  colors,  odors,  or  germs  and  their  products.  It  is 
evident  that  these  changes  can  take  place  only  in  the  presence 
of  moisture. 

Experiment. — Show  decolorizing  action  of  Cl  water  on  calico,  and 
that  the  dry  gas  has  little  effect  in  this  direction. 

Cl  tarnishes  and  corrodes  all  metals,  and  is  the  solvent  of 
Au  and  Pt  in  aqua  regia. 


118  INORGANIC  CHEMISTRY. 

Experiment. — Immerse  a  strip  of  Cu  foil  in  Cl  water,  and  note  how 
quickly  it  blackens;  also  dip  a  knife-blade  into  solution  of  HgCl2. 

Bromin. — This  element  was  first  discovered  by  Balard  in 
1826,  and  owes  its  name  to  its  strong  odor.  It  occurs  naturally 
only  in  combination  with  Mg  and  the  alkali  metals,  accompany- 
ing the  chlorids. 

It  is  separated  from  the  mother-liquor  (bittern)  of  sea- 
water — from  which  NaCl  has  been  removed  by  evaporation — 
and  salt-wells  and  springs  by  treating  the  liquid  with  Cl.  This 
element,  being  more  negative  than  Br,  has  a  greater  affinity  for 
metals,  and  drives  Br  from  its  metallic  combinations,  setting  it 
free. 

Experiment. — Shake  KBr  with  Cl  water  and  then  chloroform,  and 
note  that  the  latter  takes  up  free  Br  and  is  colored  red. 

Br  is  a  dark-reddish-brown  liquid,  very  volatile  (fuming), 
and  corrosive.  It  is  3  times  as  heavy  as  H20,  in  which  it  dis- 
solves to  the  extent  of  3  per  cent.;  it  is  more  freely  soluble  in 
alcohol,  ether,  or  chloroform. 

Br  is  less  energetic  than  Cl,  but  more  so  than  I.  Solu- 
tions of  the  element  are  decomposed  by  light,  with  formation 
of  HBr.  It  stains  organic  matter  yellow.  Great  care  should 
be  taken  not  to  allow  the  fumes  to  corrode  surgical  instruments 
or  the  metallic  parts  of  the  microscope.  If  the  hands  get 
burned  with  the  substance,  NH4HO  ought  to  be  applied  at 
once.  Though  strongly  germicidal,  Br  is  seldom  used  as  a  dis- 
infectant, because  of  its  many  disadvantages.  Its  chief  use  is 
in  the  manufacture  of  hypobromites. 

lodin. — I  was  discovered  in  1811  by  Courtois,  a  Parisian 
soap-boiler,  in  "kelp,"  or  the  ashes  of  sea-weeds.  The  name 
signifies  violet. 

I  is  found  widely  disseminated  in  the  three  kingdoms  of 
Nature,  though  not  abundant  except  in  marine  plants  (espe- 
cially laminaria),  which  absorb  it  from  the  sea-water,  as  do 
also  the  salt-water  fishes,  which  accounts  for  the  appreciable 
amount  of  I  in  codliver-oil. 

I  is  prepared  from  sea-weed  ashes  (variously  known  ac- 
cording to  locality  as  kelp,  varec,  and  barilla)  by  lixiviation  and 
evaporation  to  concentrate,  followed  by  the  addition  of  H2S04 
to  the  mother-liquor  (ppts.  S),  and  finally  distillation  of  the 
remaining  clear  liquid  in  the  presence  of  Mn02. 

2KI  +  Mn02  +  2H2S04  ==  K2S04  >f  MnS04  +  2H20  +  I2 

The  product  thus  obtained  is  usuaHy  purified  by  resub- 
limation. 


OXYGEN.  119 

This  element  is  met  with  in  the  form  of  brittle,  neutral, 
volatile,  crystalline,  purple  scales,  with  a  distinct  metallic 
luster  and  a  peculiar  odor  and  disagreeable  taste.  Its  sp.  gr.  is 
nearly  5;  m.p.,  114°;  b.p.,  180°.  It  is  very  slightly  soluble  in 
H20,  requiring  for  1  part  over  5000  of  the  latter.  Its  solution 
in  H20  is  greatly  aided  by  the  presence  of  tannin  or  KI. 
LugoPs  solution  (liquor  iodi  comp.)  is  composed  of  5  I  and  10 
KI  in  H20  to  make  100  parts.  I  is  freely  soluble  in  alcohol 
(tincture,  7-per-cent.  strength),  glycerin,  ether,  chloroform,  and 
CS2.  The  solution  in  alcohol  is  brown;  in  chloroform  or  CS2, 
violet. 

Experiment. — Heat  I  and  notice  beautiful  violet  vapor. 

I  is  the  least  energetic  of  the  halogens.  It  attacks  some 
metals,  however,  to  a  marked  degree;  its  solutions  should  not 
be  handled  in  Ag  spoons.  It  stains  the  skin  brown.  It  is  an 
irritant,  an  antiseptic,  and  a  valuable  alterative. 

Test. — With  hydrated  starch  I  gives  a  blue  color,  showing  as  little 
as  1  part  of  I  in  300,090.  On  heating  the  color  disappears,  returning 
on  cooling  if  not  all  volatilized. 

I  is  used  in  medicine,  in  photography,  and  in  the  manu- 
facture of  iodids  and  some  of  the  coal-tar  colors. 

Experiment. — To  CS2  add  S  and  an  aqueous  solution  of  I,  and  note 
violet  beads  of  SI6. 

OXYGEN. 

This  element  was  so  named  from  a  Greek  word  meaning 
sour  or  sharp,  because  it  was  formerly  believed  to  be  an  essen- 
tial element  of  all  acids.  It  is  the  most  abundant  element  in 
Xature,  making  up  nearly  1/2  of  the  earth's  crust.  It  occurs 
free  as  the  active  agent  in  air,  of  which  it  forms  about  Y5.  0 
constitutes  by  weight  8/9  of  H20,  x/2  of  sand,  and  Vs  of  clay- 
It  is  a  constituent  of  nearly  all  organic  compounds,  except 
hydrocarbons,  and  is  found  in  combination  in  every  part  of 
plants  and  animals.  It  was  discovered  by  Scheele  in  1773. 

0  is  usually  prepared  for  experimental  purposes  by  heating 
4  parts  KC103  at  200°  with  1  part  Mn02. 

2KC103  +  Mn02  =  2KC1  +  302  +  Mn02 

Experiment. — Manufacture  O  in  a  copper  retort,  and  collect  over 
H20.  ., 

As  seen  by  the  enuation,  Mn02  remains  apparently  un- 
changed A  reaction  which  is  induced  or  aided  by  the  mere 
presence  of  another  substance  is  said  to  be  catalytic  in  nature. 


120  INORGANIC  CHEMISTRY. 

When  the  Mn02  is  not  employed,  a  higher  temperature  (325°) 
is  necessary.  The  presence  of  the  Mn  compound  also  makes  the 
evolution  of  the  gas  more  steady  and  regular.  A  pound  of 
KC103  will  yield  60  or  70  quarts  of  the  gas.  On  a  large  scale 
0  is  manufactured  by  the  Brin -process,  which  consists  in  heat- 
ing to  700°  porous  BaO  in  retorts  into  which  pure  air  is  forced. 
Ba02  is  formed,  which  gives  off  0  on  reduction  of  pressure. 

0  is  a  colorless,  odorless,  tasteless  gas  a  little  heavier  than 
air:  a  liter  weighs  1.43  gm.  It  is  difficultly  liquefied,  requiring 
a  pressure  of  300  atmospheres  and  a  reduction  of  temperature 
to  — 140°,  when  it  condenses  into  a  transparent  liquid,  a  little 
lighter  than  H20.  The  critic  temperature  of  0  is  — 120°.  It 
dissolves  in  H20  to  the  extent  of  3  per  cent,  by  volume,  and 
it  is  from  this  source  that  aquatic  plants  and  animals  obtain 
the  0  necessary  to  their  existence.  0  is  the  most  magnetic  of 
all  gases. 

Experiment. — Occlude  O  with  Pt  black,  pour  on  alcohol,  and  note 
ignition. 

0  unites  with  every  element  except  F  (not  directly  with 
Au,  Pt,  and  Ag),  forming  oxids  and  oxysalts.  This  union  is 
termed  oxidation,  or  "slow  combustion,"  unless  light  as  well 
as  heat  results,  when  the  process  is  known  as  combustion. 
Substances  readily  oxidized  are  said  to  be  combustible  and  are 
composed  mainly  of  C  and  H,  the  C  being  converted  into  C02, 
and  H  into  H20.  The  C02  and  H20  given  off  by  the  lungs  and 
urea  by  the  kidneys  are  produced  by  oxidation  in  the  tissues. 
Plants  take  up  this  C02  in  sunlight,  keep  C,  and  set  free  0. 
Artificial  heat,  light,  and  mechanic  energy  are  produced  mainly 
by  oxidation. 

Experiment. — With  a  glowing  match  show  that  0  is  a  supporter  of 
combustion,  but  not  combustible. 

Some  substances  burn  in  O  that  will  not  burn  in  air. 

Experiment. — Burn  a  watch-spring  in  O,  after  attaching  to  one 
end  a  match  by  spiral  turns. 

Combustible  substances  and  supporters  of  combustion  are 
relative  terms,  since  the  union  of  two  such  substances  is  mu- 
tual. Air  or  0  can  be  made  to  burn  in  illuminating-gas  by  a 
simple  device  consisting  of  a  lamp-chimney  with  a  bottom  cork 
through  which  two  glass  tubes  pass,  one  to  admit  air,  the  other 
illuminating-gas.  When  the  gas  is  passed  in  freely,  the  flame 
leaves  this  tube  and  goes  to  the  air-tube. 

0  is  the  chemic  source  of  heat,  energy,  and  life  for  both 
plants  and  animals.  About  two  pounds  daily  are  used  up  by 
an  adult  person  in  this  way.  Plants  use  less  0  than  animals, 


SULPHUR.  121 

having  less  energy,  and  set  free  a  great  deal  more  than  they 
consume.  Animals  require  a  large  amount  of  0,  giving  off  C02 
in  return.  The  principal  subjective  effect  when  pure  0  is  in- 
haled is  a  sensation  of  warmth  in  the  upper  respiratory  tract. 
0  is  Nature's  great  antiseptic,  purifying  the  air,  water,  and  soil 
by  destroying  the  germs  of  disease  and  their  chemic  products. 

0  is  used  largely  in  respiratory  or  circulatory  affections 
with  deficient  oxygenation  of  the  blood.  It  is  also  administered 
by  inhalation  for  dangerous  chloroform  narcosis  and  poisoning 
by  coal-gas  and  other  noxious  vapors.  In  chronic  cases  1  to  5 
gallons  is  a  dose.  0  is  also  of  service  in  the  oxyhydrogen 
blow-pipe,  in  purifying  illuminating-gas  (removes  S),  and  in  the 
preparation  of  paints  and  varnishes  and  the  artificial  "aging" 
of  spirits. 

Ozone. — This  peculiar  allotropic  form  of  0  exists  in  the 
atmosphere  in  comparatively  small  quantities:  about  1  part  in 
a  million.  It  is  generated  by  heat,  light,  and  electricity;  slow 
oxidation,  rapid  combustion,  or  exposure  of  essential  oils  to 
sunlight  and  warmth.  It  is  most  abundant  at  high  altitudes, 
in  country  places,  after  thunder-storms,  in  the  spring-time, 
and  in  the  neighborhood  of  plants.  Ozone  is  triatomic.  It  may 
be  condensed  into  a  blue  liquid.  It  is  soluble  in  turpentine  or 
ether,  and  breaks  up  into  02  and  0  at  237°.  Like  H202,  it 
tarnishes  metals  and  corrodes  cork  and  rubber.  It  is  used  as 
a  bleaching  agent  and  for  "aging"  liquors.  The  word  ozone  is 
of  Greek  origin,  and  signifies  "I  smell."  The  characteristic 
irritating  odor  of  the  substance  may  be  elicited  by  dipping  a 
strongly-heated  glass  rod  into  vapor  of  ether,  or  by  mixing 
H2S04  with  K2Mn208  solution,  or  around  medical  batteries  or 
x-ray  machines. 

Experiment. — A  simple  test  for  ozone  is  hanging  a  piece  of  starch- 
paper  impregnated  with  KI  over  a  piece  of  P  partly  covered  with  ELO. 
Ozone,  being  more  negative  than  I,  displaces  the  latter,  producing  a  blue 
color  with  the  starch. 

SULPHUR. 

This  element  has  been  known  from  the  earliest  times.  In 
a  free  state,  mixed  with  earthy  matters,  it  is  found  most  abun- 
dantly in  the  vicinity  of  active  and  extinct  volcanoes,  having 
been  formed  by  the  following  reaction: — 

S02  +  2H2S  =  2H20  +  S2 

In  combination  it  is  almost  universal  in  the  sulphids  of 
the  metals,  and  is  also  of  common  occurrence  in  the  H2S  of 


122 


INORGANIC  CHEMISTRY. 


mineral  waters,  the  sulphates  of  the  alkalies  and  alkaline  earths, 
and  in  animal  and  vegetable  compounds. 

About  a  third  of  the  S  of  commerce  is  derived  from  sul- 
phid  ores.  The  remainder  comes  from  volcanic  regions,  espe- 
cially Sicily  and  other  Mediterranean  countries,  which  furnish 
annually  100,000  tons.  A  great  deal  is  obtained  from  Iceland, 
Mexico,  Central  America,  the  Sandwich  Islands,  and — in  this 
country — Santa  Barbara,  Cal.,  and  Cove  Springs,  Utah.  It  is 
also  a  considerable  by-product  in  the  manufacture  of  coal-gas, 
from  the  iron-pyrites  in  the  coal. 


Fig.  24.— Sublimation  of  Sulphur. 

S  is  separated  from  accompanying  impurities  (2  or  3  per 
cent.)  by  melting  along  with  a  little  fuel  in  furnaces  with  in- 
clined grooved  bottoms,  where  the  S  solidifies  into  rolls;  hence 
the  name  roll  sulphur  for  brimstone  (burnstone).  It  is  further 
purified  by  sublimation,  the  vapors  condensing  in  a  cooler 
chamber  into  sublimed  S,  or  flowers  of  S. 

Ordinary  S  is  a  lemon-yellow,  odorless,  nearly  tasteless, 
brittle,  crystalline  solid  (rhombic  octahedra  or  monoclinic).  It 
is  insoluble  in  all  the  ordinary  solvents  except  benzin,  turpen- 
tine, chloroform,  fixed  oils,  and  CS2  (10%7).  The  sp.  gr.  of  S 


TELLURIUM.  123 

is  about  2;  its  m.p.,  114  Y2°;  b.p.,  448°.  Melted  S  allowed  to 
cool  slowly  assumes  a  prismatic  form.  When  melted  it  is  a 
thin,  yellow  liquid,  becoming  thick  and  brown  at  250°,  turning 
lighter  again  at  330°.  Melted  S  at  about  400°,  poured  into 
H20,  forms  an  amber-colored,  elastic,  tenacious  mass  termed 
plastic  S.  This  variety  is  amorphous,  and  not  soluble  in  CS2. 

Experiment. — Make  plastic  &  by  melting  S  in  covered  vessel  and 
pouring  into  H20. 

S  is  generally  electronegative,  and  in  ternary  compounds 
may  take  the  place  of  0  as  a  linking  agent.  Its  vapor  density 
below  500°  is  96;  between  800°  and  1000°,  32.  At  ordinary  tem- 
peratures S  oxidizes  slowly,  forming  H2S03  and  H2S04.  It 
burns  with  a  blue  flame  at  230°,  forming  S02.  S  combines 
with  most  metals  and  with  many  metalloids.  Physiologically  S 
is  innocuous. 

Sublimed  S  is  used  largely  as  a  vulcanizing  material.  For 
dental  rubbers  caoutchouc  is  heated  till  soft,  then  ground  with 
15  or  20  per  cent.  S  and  subjected  to  heat,  pressure,  and  moist- 
ure. S  is  employed  extensively  in  the  manufacture  of  gun- 
powder and  matches.  Medicinally  it  is  serviceable  as  a  laxative 
(in  compound  licorice-powder)  and  in  parasiticide  ointments; 
the  latter  action  is  attributed  to  the  S02  present  in  sublimed 
S.  Plastic  S  is  used  for  taking  impressions. 

The  official  forms  comprise:  1.  S  sublimatum  (ordinary 
S).  2.  S  lotum,  or  washed  S,  from  which  the  acid  gases  have 
been  removed  with  NH4HO.  3.  S  precipitatum,  or  lac  or  milk 
S,  a  whitish,  amorphous  powder  prepared  by  the  successive 
action  on  S  of  lime  and  dilute  HC1.  4.  Unguentum  sulphuris, 
which  contains  30  per  cent,  of  S  sublimatum. 

SELENIUM. 

This  element  is  widely  distributed,  though  in  small  quan- 
tities, usually  associated  with  S.  It  appears  as  an  amorphous, 
brick-red  powder,  soluble  in  CS2;  and  as  a  crystalline,  dark- 
gray  solid,  insoluble  in  CS2.  The  element  burns  with  a  bright- 
blue  flame  and  an  odor  like  that  of  horse-radish. 

TELLURIUM. 

This  rare  element  is  found  free  or  combined  as  tellurids 
with  Au,  Ag,  and  other  metals.  It  resembles  metals  in  being 
solid  and  silver-white.  It  burns  in  the  air  with  a  blue  flame 
tinged  with  green.  Tellurids  are  recognized  by  fusing  with 
KoC03.  The  resulting  K2Te  dissolves  in  H20  with  a  red  color, 
and  on  adding  HC1  yields  a  stench  of  H2Te. 


124:  INORGANIC  CHEMISTRY. 


NITROGEN,   OR  AZOTE. 

This  element  was  first  discovered  by  Rutherford  in  1772. 
It  was  so  named  because  it  is  an  essential  element  of  niter,  or 
saltpeter.  Free  N"  constitutes  about  four-fifths  of  the  atmos- 
phere. In  combination  it  is  the  characteristic  element  of  nearly 
all  animal  substances  and  their  decomposition  products,  am- 
monia, nitrates,  nitrites,  and  cyanids.  It  is  also  present  in  a 
number  of  vegetable  compounds. 

Experiment. — Burn  P  on  a  cork  on  water  under  a  bell-jar.  The  0 
is  removed,  forming  dense,  white  fumes  of  P205,  which  is  absorbed  by 
the  water,  and  N  is  left. 

Pure  N  is  prepared  by  heating  N"H4N02  in  a  glass  retort, 
or  KN02  and  NH4C1. 


Fig.  25. — Preparation  of  Nitrogen. 

N  is  a  colorless,  odorless  gas,  a  little  lighter  than  air.  It 
liquefies  at  —  130°  under  a  pressure  of  280  atmospheres.  One 
and  a  half  volumes  of  the  gas  dissolve  in  100  of  water. 

N  is  neither  combustible  nor  a  supporter  of  combustion. 

Experiment. — Raise  lighted  candle  into  jar  of  N. 

N  is  chemically  inert  and  has  little  affinity  for  other  ele- 
ments, except  Mg,  B,  Y,  and  Ti.  Its  compounds  are  there- 
fore unstable,  decomposition  often  taking  place  with  explosive 
violence.  The  passive  nature  of  N  accounts  for  the  active  and 
dangerous  character  of  its  compounds,  such  as  nitroglycerin 
and  nitrates,  as  well,  perhaps,  for  the  physiologic  potency  of 
the  cyanids,  alkaloids,  and  other  nitrogenous  products.  It  is 
even  possible  that  on  this  same  property  depends  the  difference 


THE  AIR.  125 

between  the  dispositions  of  carnivorous  and  herbivorous  ani- 
mals. 

N  gas,  though  non-poisonous,  is  not  directly  utilized  by 
the  system.  Its  presence  in  inhaled  air  is  needed  to  prevent 
too  rapid  oxidation  of  the  tissues.  N  is  occasionally  employed 
as  a  medium  for  chemic  processes  from  which  0  must  be 
excluded. 

Experiment. — Make  NI3  by  treating  tincture  of  iodin  with  excess 
of  NH4HO.  Collect  ppt.  on  filter-paper  and  put  a  few  grains  on  several 
separate  bits  of  paper.  On  drying  it  explodes  at  the  slightest  touch. 

THE  AIR. 

Until  1772  air  was  considered  to  be  an  element.  Air  is 
a  mechanic  mixture,  and  not  a  compound.  This  is  proved  by 
the  facts  that  its  constitution  is  not  absolute,  that  when  ab- 
sorbed by  H20  the  N  and  0  are  not  in  the  same  proportion 
as  in  the  atmosphere,  and  that  there  are  no  chemic  phenom- 
ena on  mixing  N  and  0.  The  principal  gases  in  air  are  0  and 
1ST,  in  the  proportion,  by  weight,  of  23  per  cent,  of  the  former 
and  76  per  cent,  of  the  latter;  by  volume,  20.61  per  cent,  of 
0  and  77.95  per  cent,  of  N.  Argon  constitutes  about  1  per 
cent,  of  the  atmosphere,  and  was  discovered  by  Kayleigh  and 
Eamsey  in  1894  by  removing  from  air  both  the  0  (with  red- 
hot  Cu  turnings)  and  the  N  (with  red-hot  Mg)  as  well  as  H20 
and  C02.  Argon  is  the  most  inert  element  known,  and  its  name 
signifies  no  energy.  Helium  is  another  gas  lately  discovered  in 
our  atmosphere  (1  to  10,000),  and  already  noticed  in  the  solar 
spectrum;  hence  its  name.  Coronium  is  another  atmospheric 
gas,  found  in  volcanic  vapors,  and  showing  a  characteristic 
green  line  in  the  solar  spectrum.  It  appears  to  be  lighter  than 
H,  and  both  this  element  and  He  may  be  compounds  of  H, 
which  also  exists  in  the  atmosphere  in  traces:  2  parts  in  10,000. 
Krypton  is  the  latest  discovered  atmospheric  element,  found 
in  the  residue  left  from  liquefying  A.  There  are  also  traces  of 
neon  and  metargon.  All  of  these  minor  gases  are  monatomic 
and  inert. 

Water-vapor  is  present  in  air  to  the  extent  of  0.75  to  1.5 
per  cent.  (3  to  16  volumes  per  1000).  C02  in  the  atmosphere 
should  not  exceed  4  parts  in  10,000. 

Liquid  air  is  now  made  on  a  commercial  scale  by  machin- 
ery. The  air  is  subjected  to  a  pressure  of  a  ton  to  the  square 
inch,  and  at  the  same  time  allowed  to  escape  through  a  very 
fine  orifice.  Much  heat  is  absorbed  in  expansion,  and  by  re- 
peating the  operation  three  times  the  temperature  is  lowered 


12(3  INORGANIC  CHEMISTRY. 

to  or  below  — 191°,  at  which  point  liquefaction  takes  place. 
Liquid  air  is  faintly  blue.  In  open  vessels  it  evaporates  rap- 
idly; the  N",  being  somewhat  more  volatile,  is  given  off  more 
rapidly  than  0.  Even  at  this  temperature  of  about  —  200°  the 
0  residue  is  an  energetic  supporter  of  combustion.  Soft  and 
elastic  organic  substances  and  metals  become  very  brittle  when 
immersed  in  this  fluid.  Liquid  air  has  been  used  to  some  ex- 
tent in  medicine  as  a  caustic  application:  e.g.,  in  lupus.  In  the 
future  it  is  likely  to  find  very  extensive  use  as  a  cooling  agent 
for  rooms  in  hot  weather.  The  density  of  liquid  air  is  0.9. 

According  to  Hinrichs,  the  real  atmosphere,  containing 
aqueous  vapor  and  clouds,  forms  a  stratum  12  miles  in  height. 
Its  density  decreases  with  increase  of  altitude,  as  shown  by  the 
barometer.  At  the  ocean-level  air  is  14.44  times  as  heavy  as  H, 
and  a  liter  weighs  1.29  gm.  The  0  atmosphere  reaches  to  30 
miles,  at  which  height  0  is  reduced  to  10  per  cent.  The  N" 
atmosphere  (reduced  from  86  per  cent,  to  4  per  cent.)  extends 
to  60  miles  above  the  earth.  The  He,  or  auroral,  atmosphere 
is  the  fourth  stratum,  and  gradually  gives  way  to  H,  which  at 
a  height  of  100  miles  constitutes  90  per  cent.,  by  volume,  of 
the  air. 

PHOSPHORUS. 

The  word  phosphorus  means  the  light-bearer  and  indicates 
the  combustible  nature  of  this  element.  P  was  discovered  in 
1669  by  the  German  alchemist  Brandt,  by  distilling  urine  with 
sand. 

This  element  does  not  occur  free  in  Nature.  It  was  pri- 
marily combined  with  0  in  the  ancient  rocks,  which  on  dis- 
integration furnished  P  for  plants,  and  these  to  animals.  The 
principal  natural  compound  is  rock  phosphate,  Ca3(P04)2,  which 
is  made  up  largely  of  the  bones  of  prehistoric  animals.  It  is 
found  in  veins  in  the  rocks  of  certain  regions,  especially  near 
Charleston  and  Memphis,  and  is  also  present  in  small  amounts 
everywhere. 

P  is  prepared  by  treating  bone-ashes  or  the  mineral  som- 
brerite  [impure  Ca3(P04)2]  with  an  equal  volume  of  50  per 
cent.  H2S04,  yielding  CaS04  and  CaH4(P04)2.  The  latter  salt 
on  heating  to  redness  loses  two  molecules  of  H20,  and  is 
thereby  changed  into  the  metaphosphate,  Ca(P03)2,  which  is, 
in  part,  reduced  to  P  by  charcoal  with  the  aid  of  a  white  heat 
or  by  distilling  with  sand.  The  crude  P  thus  obtained  is  puri- 
fied by  redistillation,  and  is  allowed  to  solidify  in  molds  of 
glass  or  Cu. 


PHOSPHORUS.  127 

This  element  has  four  allotropic  forms:  two  white,  a  red, 
and  a  black.  The  ordinary  stick,  or  white,  octahedral  P  is  of  a 
translucent,  waxy  appearance;  sp.  gr.,  1.83;  m.p.,  44°.  It  can 
be  cut  with  a  knife,  and  has  a  characteristic  odor.  It  is  in- 
soluble in  H20,  slightly  soluble  in  ether  and  in  alcohol  (1  to 
350),  and  quite  soluble  in  chloroform.  The  best  practicable 
solvents  for  it  are  fixed  oils  (1  to  50),  though  CS2  is  most  effi- 
cient, dissolving  20  times  its  own  weight  of  P,  the  solution 
being  spontaneously  inflammable  on  exposure  to  the  air. 

Eed,  or  "amorphous,"  P  is  prepared  by  heating  the  ordi- 
nary variety  at  300°  in  a  closed  iron  vessel  filled  with  N  or 
C02.  It  is  generally  insoluble,  not  so  inflammable  as  the  white 
variety,  and  has  a  sp.  gr.  of  2.14.  It  is  reconverted  into  ordi- 
nary P  on  heating  to  280°.  The  third  variety — called  black, 
or  metallic,  P — appears  in  the  form  of  dark-red,  rhombohedral 
crystals;  sp.  gr.,  2.34.  It  is  made  by  heating  waxy  P  along 
with  Pb  at  a  little  below  red  heat  in  sealed  tubes  for  10  or  12 
hours,  after  which  the  Pb  is  dissolved  out  with  dilute  HN03. 
A  fourth  variety,  white  and  flaky,  is  prepared  by  distilling 
ordinary  P  in  an  atmosphere  of  H. 

Ordinary  P  is  very  oxidizable,  igniting  spontaneously  in 
air  at  from  50°  to  60°.  At  lower  temperatures  it  oxidizes  more 
slowly,  with  phosphorescence.  To  prevent  spontaneous  com- 
bustion, it  is  kept  under  H20.  When  partly  exposed  to  the  air 
it  evolves  white  fumes  of  P205,  and  also  ozone  and  H202.  P 
combines  directly  with  all  the  common  elements  except  C,  H, 
and  N.  Red  P  is  much  more  inert  than  the  white,  not  igniting 
below  260°.  The  black  variety  is  the  least  active. 

Experiment. — Make  fire  under  water  by  placing  in  a  conic  glass 
of  H,O  a  few  bits  of  P  and  some  crystals  of  KC1O3,  adding  to  these  by 
means  of  a  pipet  some  H2SO4. 

Experiment.— Make  H3P  by  boiling  P  with  KHO,  first  expelling 
air  in  the  flask  by  dropping  in  a  few  drops  of  ether.  Keep  the  beak  of 
the  retort  under  water,  and  note  how  the  bubbles  ignite  as  they  appear 
at  the  surface  and  the  curious  rings  of  P2O5  that  are  formed. 

Phosphin,  H3P,  is  a  colorless  gas  with  an  odor  like  garlic, 
formed  in  Nature  by  the  putrefaction  of  organic  substances 
under  water.  When  mixed  with  P2H4  (a  liquid)  it  is  spon- 
taneously combustible.  This  is  the  ignis  fatuus,  or  will-o'-the- 
wisp,  of  marshy  places. 

P  and  its  compounds  are  used  extensively  in  medicine  for 
building  up  the  bony  and  nervous  tissues.  P  matches  are  made 
by  dipping  the  wooden  slips  tipped  with  paraffin  or  S  in  a 
mixture  of  glue  and  P,  to  which  have  been  added  other  in- 
gredients— such  as  Mn02,  KN03,  chalk,  S,  lamp-black  and 


128  INORGANIC  CHEMISTRY. 

other  oxidizers,  combustibles,  and  hard  substances — to  increase 
friction.  Parlor-matches  crackle  because  of  the  quick  com- 
bustion, due  largely  to  KC103.  Safety-matches  contain  no  P, 
but  Sb2S3,  Pb304,  and  KC103,  or  K2Cr207.  In  order  to  ignite 
them  they  must  be  rubbed  on  a  surface  composed  of  red  P  and 
Sb2S5.  The  gritty  nature  of  the  latter  compound  makes  the 
friction  greater.  Eed  P  is  slightly,  if  at  all,  toxic,  and  is  used 
in  Europe  for  making  matches,  in  place  of  the  white  variety, 
which  is  still  employed  almost  exclusively  in  this  country. 

A  simple  test  for  P  is  to  heat  in  a  test-tube  with  acidulated 
water,  and  note  the  phosphorescence.  Filter-paper  dipped  in 
AgN03,  held  above  the  mouth  of  the  tube,  is  colored  dark  by 
formation  of  silver  phosphid. 

The  official  preparations  of  P  are  three  in  number.  Oleum 
phosphori  contains  1  per  cent,  of  P  dissolved  in  sweet  almond- 
oil.  Pilule  phosphori  contain  Yioo  grain  of  P,  and  are  coated 
with  balsam  of  Tolu.  The  spirit  or  tincture  of  P  is  made  with 
absolute  alcohol,  and  has  1.2  parts  of  P  in  a  thousand. 


BORON. 

This  element  was  first  isolated  by  Davy  in  1808.  The 
name  is  derived  from  an  Arabic  word  meaning  to  shine,  and 
referring  to  the  incrusted  shores  of  borax  lakes.  It  is  found 
in  the  natural  state  only  in  combination,  chiefly  as  borax  and 
boric  acid. 

B  appears  as  a  brown  or  yellow,  amorphous  powder  or 
octahedral  crystals.  These  crystals  are  infusible  and  next  to 
the  diamond  in  hardness,  and  have  a  sp.  gr.  of  2.68.  At  high 
temperatures  B  combines  directly  with  N. 


SILICON,   OR   SILICITJM. 

This  element  was  so  called  from  the  Latin  word  silex9 
meaning  flint.  It  was  first  isolated  by  Berzelius  in  1823. 

Next  to  0,  Si  is  the  most  abundant  element  in  Nature. 
It  is  never  found  free.  It  is  the  chief  constituent  of  nearly 
all  rocks  and  soils,  and  is  present  in  plant-ashes  and  to  a  much 
less  extent  in  animal  tissues. 

Si  may  be  prepared  by  heating  together  K2SiF6  and  K4. 
When  thus  obtained  it  appears  as  dark,  lustrous  octahedra,. 
hard  enough  to  scratch  glass,  and  with  a  sp.  gr.  of  2.5.  It  may 
also  be  procured  in  amorphous  and  graphitic  forms  correspond- 
ing with  those  of  C. 


CARBON.  129 


CARBON. 

C  in  all  its  forms  was  known  to  the  ancients.  Its  name  is 
derived  from  carlo:  Latin  for  charcoal. 

C  is  found  in  Nature  in  three  allotropic  forms:  two  crystal- 
line (diamond  and  graphite),  one  amorphous,  including  coal, 
charcoal,  coke,  lamp-hlack,  and  gas-retort  carbon.  The  dia- 
mond is  the  hardest  substance  known.  It  is  3  1/z  times  as 
heavy  as  H20,  and  crystallizes  in  cubes  or  octahedra.  Its 
brilliancy  depends  on  internal  reflection  of  light,  owing  to  its 
great  refractive  power.  The  best  diamonds  are  found  in  the 
gravel-beds  of  Brazil  and  South  Africa.  These  are  worn  as 
gems;  small  and  imperfect  ones  are  used  in  glass-cutters, 
miners'  drills,  and  rock-boring  machines.  Microscopic  dia- 
monds are  found  in  steel  made  by  the  Bessemer  process.  The 
carat,  or  special  unit  of  weight  for  diamonds,  is  equal  to  3.17 
grains. 

Graphite  (plumbago,  black  lead)  crystallizes  in  unctuous 
hexagonal  prisms;  sp.  gr.,  2;  is  almost  infusible,  and  is  a  good 
conductor  of  electricity.  On  account  of  its  non-oxidizability, 
this  substance  is  much  used  as  a  protective  and  lubricant:  e.g., 
in  stove-polish  and  for  machinery  and  bicycle-chains.  It  is  also 
used  in  painting  metals,  electrotyping,  glazing,  gunpowder,  as 
a  mold-wash,  and  mixed  with  clay  and  sand  in  crucibles.  It 
owes  the  name  graphite  to  the  use  which  is  made  of  it  in  pen- 
cils. The  best  quality  is  from  a  mine  at  Cumberland,  Eng. 

All  the  amorphous  varieties  of  C  are  derived  by  natural  or 
artificial  incomplete  combustion  of  the  vegetable  growth  of  the 
past  or  the  present.  Coal,  for  example,  is  the  product  of  the 
changes  effected  in  the  forests  of  long  ago  by  great  pressure 
and  terrestrial  heat  (due  to  changes  in  the  earth's  crust)  with- 
out access  of  air,  driving  out  more  or  less  the  liquids  and  gases 
of  the  trees  and  other  plants  from  which  the  coal  was  formed. 
According  to  the  relative  completeness  of  carbonization,  there 
are  several  kinds  of  coal.  Anthracite,  or  "hard,"  coal  contains 
hardly  any  volatile  products;  hence  on  burning  it  glows,  but 
does  not  yield  a  flame.  Bituminous,  or  "soft,"  coal,  on  the  other 
hand,  has  not  undergone  so  much  pressure.  It  is  rich  in  petro- 
leum (from  which  coal-oil  is  made)  and  in  gaseous  compounds; 
hence  it  burns  with  flame,  or,  if  heated  in  suitable  retorts  in 
the  absence  of  0,  the  gases  may  be  separated  from  the  solid 
coal  and  be  utilized  as  illuminating  gas  or  for  heating  purposes. 
The  residue  of  solid  coal  left  in  the  retorts  is  termed  gas-carbon 
or  plumbagin.  It  is  hard,  compact,  and  difficult  to  fuse,  and 
is  much  used  for  electrodes  and  battery-plates.  Cannel-coal 


130  INORGANIC  CHEMISTRY. 

is  a  compact  subvariety  of  bituminous,  and  was  so  named  be- 
cause on  combustion  it  gives  a  steady  light  like  that  of  a  candle. 
Lignite,  brown,  and  wood  coal,  as  the  names  indicate,  are  soft 
coals  nearer  to  the  woody  nature  of  the  coal-forming  plants 
than  is  ordinary  bituminous  coal.  It  is  most  abundant  in  the 
Eocky  Mountain  regions.  Jet  is  a  peculiar  kind  of  coal,  so 
called  because  it  is  capable  of  taking  a  fine  polish.  Peat  is  a 
carbonaceous  fuel  made  up  of  partly-carbonized  vegetation 
mixed  with  mud.  It  is  obtained  in  great  quantities  from  the 
boggy  districts  of  Ireland. 

Wood-charcoal  (carbo  ligni)  is  made  from  piles  of  wood 
(U.  S.  P.,  soft  willow-twigs)  by  burning  the  latter  with  little 
air:  that  is,  covered  with  earth.  The  wood  consumed  yields 
about  YB  its  weight  of  charcoal.  Carbo  ligni  is  a  light,  porous 
powder,  noted  for  absorbing  gases — 90  volumes  of  NH3  at  ordi- 
nary temperatures,  or  about  twice  as  much  at  f.p.  Because  of 
this  property,  wood-charcoal  is  much  employed  as  a  deodorizer 
to  occlude  H2S  and  other  foul  gases.  It  is  also  used  internally 
for  the  same  reason,  in  fermentive  digestive  disorders  and  as 
an  antidote  for  poisons.  The  antiseptic  power  of  charcoal  is 
very  slight.  Wood-charcoal  is  employed  as  a  fuel  in  metallurgy 
and  in  the  manufacture  of  crucible  and  cementation  steel. 

Experiment. — Introduce  a  piece  of  heated  charcoal  into  a  test-tube 
previously  filled  with  NH3  over  Hg,  and  note  rise  of  the  metal,  owing 
to  absorption  of  the  gas. 

Animal  charcoal  (bone-black,  ivory-black,  carbo  animalis) 
is  prepared  by  the  destructive  distillation  of  bones  in  much 
the  same  manner  as  the  ligneous  variety  is  obtained.  The 
crude  product  is  purified  by  treating  with  dilute  HC1,  which 
dissolves  out  any  Ca3(P04)2.  Bone-charcoal  is  employed  largely 
for  decolorizing  sugar  and  purifying  petroleum,  and  also  in 
boot-blacking  and  along  with  sand  in  water-filters.  Carbonized 
blood  is  similar  to  bone-black,  and  is  used  for  the  same  pur- 
poses. 

Coke  is  obtained  from  coal  much  in  the  same  way  as  char- 
coal is  from  wood.  It  burns,  of  course,  without  flame,  but 
furnishes  a  steady,  intense  heat. 

Lamp-black  is  the  collected  smoke  of  burning  tar,  rosin, 
turpentine,  or  petroleum,  with  a  limited  supply  of  air.  It  is 
identic  with  the  soot  of  chimneys  and  lamp-chimneys,  and  has 
wide  use  in  black  paints  and  printers'  and  India  ink.  Certain 
woods,  as  pinon,  are  much  richer  in  carbonaceous  resins  than 
others,  and  hence  soon  fill  up  a  chimney  with  soot. 

Experiment. — Burn  camphor  or  turpentine  in  a  wide-mouth  bottle, 
and  notice  lamp-black  formed. 


OXIDS.  131 

Free  C  in  any  form  is  soluble  only  in  molten  cast-iron, 
forming  a  binary  compound,  called  carbid,  with  the  metal.  A 
part,  however,  usually  crystallizes  out  as  graphite  on  cooling. 
C  is  fused  and  volatilized  only  by  the  electric  arc  light.  It  is 
not  oxidized  at  ordinary  temperatures,  but  at  high  ones  has  a 
great  affinity  for  0.  Hence  in  the  form  of  fuel  it  is  much  used 
as  a  reducing  agent  in  smelting  and  as  charcoal  supports  in 
assaying.  C  unites  directly  with  very  few  elements,  indirectly 
with  a  great  many.  In  combination  C  is  present  in  all  plants 
and  animals,  in  most  combustibles,  and  in  fats,  oils,  and  car- 
bonates. C  and  H  are  the  fuel-elements  of  the  food.  C  in 
combination  is  readily  shown  by  the  substance  charring  on 
heating. 

Though  the  elements  As  and  Sb  are  more  closely  allied  to 
metalloids  than  to  metals,  they  will  be  considered,  for  prac- 
tical convenience,  with  the  latter  groups. 


OXIDS. 

This  class  of  compounds  may  be  divided  into  neutral 
(water),  basic,  and  acid  oxids. 

Water,  H20,  is  the  most  abundant  compound  in  Nature. 
It  constitutes  65  or  70  per  cent.,  by  weight,  of  the  human  body, 
and  is  present  in  large  amounts  in  both  plants  and  animals,  and 
also  in  most  minerals  as  water  of  crystallization.  Like  air,  it 
was  thought  to  be  an  element  until  decomposed  with  electricity 
by  Lavoisier  in  1783.  It  occurs  in  Nature  in  three  forms,  being 
solid  below  0°,  gaseous  above  100°  (at  sea-level),  and  liquid 
between  these  temperatures. 

Experiment. — Prove  that  dry  wood  contains  H20  by  heating  a 
match-stick  in  a  glass  tube  sealed  at  one  end. 

Water  is  composed  of  H  and  0,  2  volumes  of  the  former  to 
1  of  the  latter,  the  3  volumes  becoming  condensed  to  2;  or,  by 
weight,  8  parts  of  0  to  1  of  H.  The  molecular  weight  of  H20 
is  18;  density  of  water-vapor,  9. 

Experiment. — Decompose  H20  by  electrolysis,  and  prove  identity 
of  gases.  A  little  acid  hastens  the  process. 

Water  is  produced  in  four  ways:  1.  By  direct  union  of  H 
and  0  through  the  agency  of  electricity  in  a  eudiometer  or  by 
burning  H  in  air.  2.  By  oxidation  or  combustion  of  substances 
containing  H.  One  to  two  pounds  of  H20  is  formed  daily  in 
the  human  body  in  this  way.  3.  By  the  action  of  an  acid  on 


132  INORGANIC  CHEMISTRY. 

a  base  or  metallic  oxid.  4.  In  the  reduction  of  a  metallic  oxid 
byH. 

Pure  H20  is  a  colorless,  tasteless,  odorless,  transparent, 
mobile  liquid.  In  large  quantities  it  appears  blue  or  green.  It 
is  773  times  as  heavy  as  air.  The  greatest  density  of  water  is 
at  4°  C.,  at  which  point  it  is  taken  as  the  standard  of  specific 
gravity.  Below  this  temperature,  as  well  as  above,  it  becomes 
lighter,  expanding  one-eleventh  in  changing  to  ice.  It  is  the 
most  universal  solvent,  and  hence  is  never  found  absolutely 
pure  unless  distilled.  It  is  a  poor  conductor  of  heat  and  elec- 
tricity, though  better  than  air. 

The  f.p.  of  H20  is  raised  by  anything,  as  rise  in  altitude, 
which  diminishes  pressure;  and  the  same  circumstances  have 
the  effect  of  lowering  the  b.p.  Conversely,  the  b.p.  under  a 
pressure  of  25  atmospheres  is  224°.  The  presence  of  salts  in 
solution  lowers  the  f.p.  and  raises  the  b.p.  When  water  freezes 
it  forms  hexagonal  crystals,  best  seen  in  the  form  of  snow- 
flakes;  slight  agitation  favors  the  process  of  congelation. 
When  water  vaporizes  it  expands  to  1700  times  the  former 
volume;  hence  the  power  of  steam.  The  great  superiority  of 
steam-sterilization  over  hot-air  depends  on  the  great  amount 
of  latent  heat  in  steam. 

Water  is  a  very  stable  compound,  dissociation  not  taking 
place  under  1000°.  It  is  neutral  in  reaction,  and  is  therefore 
used  very  largely  as  a  solvent  for  medicines  and  chemic  re- 
agents. It  unites,  however,  with  metallic  oxids  to  form  bases 
or  hydroxids,  and  with  negative  oxids  to  form  acids,  and  is 
decomposed  by  a  few  of  the  most  positive  metals  with  evolution 
of  H. 

Experiment. — Show  that  CO2  and  H2O  make  an  acid. 
Experiment. — Show  that  CaO  and  H20  make  a  base. 

Deliquescent  substances,  those  which  are  very  soluble  in 
H20  and  take  it  from  the  air  to  be  dissolved  in,  are  used  in  the 
drying  of  gases  and  precipitates.  Examples  of  such  drying 
agents  are  CaCl2,  H2S04,  and  P205.  The  water  of  crystalliza- 
tion of  minerals  is  held  in  place  by  a  feeble  chemic  union 
(hydration)  with  the  salt  proper  of  the  substance,  and  is  readily 
separated  by  heating  at  100°  to  120°,  or,  in  the  case  of  efflores- 
cent substances  especially,  by  simple  exposure  to  the  air.  Many 
medicinal  mineral  salts  contain  a  large  proportion  of  water  of 
crystallization. 

Water  is  of  more  immediate  necessity  to  the  system  than 
is  solid  food.  It  serves  in  the  body  to  assist  in  processes  of 
solution,  secretion,  excretion,  circulation,  and  the  regulation 


METALLIC,  OR  BASIC,  OXIDS.  133 

of  heat  by  evaporation.    Five  or  6  pints  daily  should  be  taken 
by  adults  in  food  and  drink. 

The  official  forms  of  water  are  as  follows:  Aqua  is  the 
Latin  name  for  natural  water.  Aqua  destillata  is  prepared  by 
distilling  80  parts  of  pure  natural  water,  the  first  2  and  the 
last  14  parts  being  rejected  in  order  to  prevent  contamination, 
in  the  first  place  with  gases,  and  at  the  end  of  the  process  with 
solid  matters.  The  preparations  called  aquae  are  solutions  in 
distilled  H20  of  a  gaseous  or  volatile  substance.  Those  made 
from  the  volatile  oils  (peppermint,  anise,  etc.)  contain  1  minim 
of  the  oil  to  each  ounce  of  the  solvent,  solution  being  accom- 
plished with  the  aid  of  cotton.  Liquors  are  aqueous  solutions 
of  fixed  and  solid  bodies:  e.g.,  liquor  potassse,  liquor  calcis. 
Decoctions  are  aqueous  solutions  of  vegetable  substances,  pre- 
pared by  placing  the  given  substance  in  boiling  water  for  ten 
or  fifteen  minutes.  Infusions  are  vegetable  solutions  made  with 
water  at  a  temperature  below  the  b.p.  By  maceration  in  chem- 
istry is  understood  the  continued  action  on  a  substance  of  H20 
at  ordinary  temperatures;  when  such  extraction  of  medicinal 
agents  is  made  with  boiling  H20,  the  process  is  termed  diges- 
tion. The  separation  of  an  alkali  salt  from  its  insoluble  im- 
purities is  called  lixiviation;  leaching  ashes  is  a  common  ex- 
ample. 

METALLIC,   OR   BASIC,   OXIDS. 

These  are  solid  substances  obtained  by  burning  the  metal 
in  air  or  heating  its  hydroxid  or  carbonate.  They  are  all  in- 
soluble as  such  in  water,  but  dissolve  in  acids  without  efferves- 
cence, forming  salts.  Oxids  of  the  alkalies  and  alkaline  earths 
combine  with  H20  to  form  hydroxids,  which  are  more  or  less 
soluble.  Peroxids  are  ready  oxidizing  agents. 

Identification  of  Oxids. — Mainly  by  negative  reactions.  No  change 
when  heated  alone,  except  HgO  (volatilizes  and  separates  into  elements) 
and  AgO  (leaves  metal). 

After  dissolving  in  an  acid  and  removing  metal  with  ELS  or  Na2CO3, 
no  acid  radical  is  found  except  that  of  solvent.  Boiling  or  fusion  with 
alkalies  is  also  negative. 

Peroxids  give  off  O  when  strongly  heated,  and  evolve  Cl  when 
heated  with  HC1. 

Potassium.  —  This  metal  has  three  oxids,  the  monoxid, 
K20;  peroxid,  K02;  and  suboxid,  K40.  The  first  is  a  white 
powder  obtained  by  heating  the  metal  in  dry  air.  It  becomes 
red  hot  when  moistened  with  H20.  The  second  is  a  yellow 
mass  obtained  by  heating  the  metal  in  excess  of  0.  When  the 


134  INORGANIC  CHEMISTRY. 

metal  is  burned  in  insufficient  air  an  unstable  blue  compound, 
K40,  is  formed. 

Sodium.  —  The  monoxid,  Na20,  is  a  gray  mass  combining 
violently  with  H20.  The  peroxid,  Na202,  is  a  very  caustic, 
light-yellow  powder,  used  as  an  oxidizing  and  bleaching  agent. 
On  mixing  with  H20  it  yields  about  20  per  cent,  of  0. 


Na202  +  H20  =  2NaHO  +  0 

Lithium.  —  Li90  is  a  white  crystalline  mass  uniting  with 
H20  to  form  LiHO. 

Calcium.  —  CaO  (lime,  quicklime,  calx)  is  obtained  by  burn- 
ing limestone  with  alternate  layers  of  fuel  in  a  kiln. 


CaC0  =  CaO       C0 


It  is  a  gray-white,  infusible  solid,  with  a  sharp,  caustic, 
alkaline  taste.  It  is  a  good  drying  agent,  and  is  used  in  many 
industries.  In  the  oxyhydrogen  flame  a  stick  of  lime  produces 
the  intensely  white  Drummond,  or  calcium,  light.  On  exposure 
to  the  air  lime  slakes:  that  is,  becomes  converted  into  a  mixture 
of  hydrate  and  carbonate  by  absorption  of  H20  and  C02. 

Strontium.  —  SrO  is  a  gray-white  powder  used  in  sugar 
manufacture.  Sr02  appears  as  a  light,  white  powder. 

Barium.  —  BaO  is  a  light-gray,  porous  mass  used  in  the 
manufacture  of  C.  Ba02  is  a  light-gray  or  yellowish,  coarse 
powder  used  for  the  preparation  of  H202. 

Magnesium.  —  Magnesia,  MgO,  is  prepared  on  a  large  scale 
by  calcining  at  a  red  heat  the  carbonate,  the  light  (calcined) 
or  heavy  (ponderosa)  variety  being  formed  according  as  the 
light  or  heavy  carbonate  is  used.  Compact  magnesia  is  made 
by  heating  the  nitrate  or  chlorid  just  to  bright  redness.  MgO 
is  a  loose,  white  powder  of  an  earthy  taste.  The  official  light 
magnesia  is  3  1/2  times  as  bulky  as  the  same  weight  of  heavy 
magnesia.  MgO  is  used  as  a  face-powder,  an  antacid  laxative, 
and  an  antidote  for  arsenic  and  corrosive  acids.  It  is  nearly 
insoluble  in  H20,  with  which  it  forms  the  hydrate,  which  is 
dissolved  by  NH4C1  (used  to  separate  Mg  from  Ca).  A  mixture 
of  compact  MgO,  H20,  and  chalk  or  marble-dust  is  used  as  a 
filling  for  decayed  teeth. 

Zinc.  —  ZnO  is  a  white,  floury  powder  much  used  in  astrin- 
gent ointments  and  also  in  paints;  it  does  not  darken  with 
H2S.  It  turns  yellow  on  heating.  It  is  used  as  a  source  of 
other  Zn  compounds.  The  purest  ZnO  is  made  by  igniting  the 
carbonate. 

Dental  cements  are  made  with  dehydrated  ZnO  as  a  basis 


METALLIC,  OR  BASIC,  OXIDS.  135 

and  a  liquid.  The  cement  commonly  employed  is  Oxyphosphate, 
a  solution  of  ZnO  in  pure  glacial  phosphoric  acid.  Oxychlorid 
cement  consists  chiefly  of  ZnO  and  a  solution  of  ZnCl2  (sp.  gr., 
1.5);  Oxysulphate,  of  ZnO  and  ZnS04  in  powder  and  ZnCl2  so- 
lution, or  solution  of  gum  arabic  and  a  little  CaS03.  The 
powder  and  liquid  are  mixed  thoroughly  on  glass  or  porcelain 
with  a  stiff  spatula  until  a  putty-like,  elastic,  non-adhesive  mass 
is  produced.  Silica,  borax,  and  ground  glass  are  often  added 
to  make  "set"  mass  harder  and  less  contractile.  The  various 
shades  of  color,  from  light  cream  to  dark  yellow,  are  secured 
by  proper  manipulation  of  the  heat  in  calcining  the  ZnO:  dark 
yellow  requires  a  white  heat  for  two  hours.  Dental  cements 
are  broken  up  by  either  alkalies  or  acids.  Oxyphosphate  is  the 
most  durable  cement.  The  oxychlorid  is  irritant,  but  some- 
what antiseptic,  and  is  used  for  lining  cavities  prior  to  filling. 
Oxysulphate  is  non-irritant,  but  deficient  in  hardness,  and  is 
used  for  protecting  pulps.  All  cements  are  more  or  less  porous. 

Experiment.  Oxyphosphate  Cement. — To  prepare  powder  weigh 
out  45  gm.  of  crude  ZnO,  moisten  with  HN03,  and  apply  gentle  heat, 
constantly  stirring  with  glass  rod  until  brown  fumes  cease.  Then  trans- 
fer powder  to  clean  clay  crucible  and  apply  white  heat  in  furnace  for 
an  hour  or  two.  Remove  from  furnace,  pulverize  in  mortar,  sift  through 
fine  cloth,  and  bottle  in  three  equal  parts.  To  prepare  liquid  add  a  few 
pieces  of  glacial  phosphoric  acid  to  10  or  15  c.c.  of  distilled  H20  in  test- 
tube;  heat  gently  from  time  to  time,  adding  more  acid  till  liquid  is  like 
glycerin  in  consistence;  then  filter  and  bottle.  To  make  the  cement 
pour  liquid  and  solid  near  each  other  on  mixing  plate,  adding  the  powder 
little  by  little  to  the  liquid  and  spatulating  until  a  homogeneous  mass 
is  obtained. 

Experiment.  Oxychlorid  Cement. — To  10  gm.  of  calcined  ZnO  add 
and  mix  thoroughly  0.1  gm.  of  borax  and  0.2  gm.  of  silica.  Calcine  in 
clay  crucible  in  furnace  at  bright-red  heat  for  a  half -hour  or  more; 
then  remove,  pulverize,  sift,  and  bottle.  For  the  liquid  portion  dissolve 
granular  Zn  piece  by  piece  in  10  c.c.  of  HC1,  and  heat  gently  till  acid  is 
saturated ;  then  filter  through  glass  wool  and  preserve  in  well-stoppered 
bottle.  The  mixing  process  is  the  same  as  for  Oxyphosphate. 

Experiment.  Oxysulphate  Cement. — Mix  10  gm.  of  calcined  ZnO 
with  4  gm.  of  dry  ZnSO4.  Place  mixture  in  clay  crucible  and  calcine  in 
furnace  as  for  oxychlorid;  then  pulverize,  sift,  and  bottle.  The  liquid 
portion  is  obtained  by  dissolving  2  gm.  of  ZnCl2  in  10  c.c.  of  H2O.  In 
mixing  the  two  portions  the  powder  is  added  only  until  a  cream-like 
mass  is  obtained. 

Copper. — The  cuprous  compound,  Cu20,  is  a  red  powder, 
soluble  in  NH4HO.  It  is  used  to  give  a  red  color  to  glass. 
Cupric  oxid,  CuO,  is  an  amorphous,  dark-brown  or  yellow  pow- 
der, soluble  in  NH4HO.  In  the  presence  of  organic  substances 
it  gives  up  0  readily,  and  is  much  employed  in  organic  analysis. 
It  is  also  the  coloring  matter  in  artificial  emeralds.  CuO  forms 


136  INORGANIC  CHEMISTRY. 

with  H3P04  a  hard  and  tenacious  black  mass  sometimes  used 
as  a  filling  for  teeth. 

Experiment. — Heat  in  a  hard  tube  a  pinch  of  sugar  with  about  ten 
times  as  much  CuO  until  a  coppery  residue  shows  reduction. 

Mercury. — Hg20  is  a  dark-brown  powder  used  in  medicine 
as  "black  wash,"  made  by  the  reaction  between  calomel  and 
lime-water,  4  grains  to  the  ounce. 

Hg2Cl2  +  Ca(HO)2  =  Hg20  +  CaCl2  +  H20 

HgO  appears  in  two  colors:  rubrum  and  flavum.  The  red 
crystalline  variety  is  prepared  by  dissolving  Hg  in  three  times 
as  much  25-per-cent.  HN~03  and  evaporating;  the  resulting 
basic  mercuric  nitrate  is  rubbed  thoroughly  with  10  parts  Hg 
to  convert  to  the  corresponding  ous  salt,  from  which  HgO  is 
sublimed.  The  yellow,  amorphous  oxid  is  prepared  by  reaction 
between  HgCl2  and  NaHO.  It  is  the  chief  ingredient  of  "yellow 
wash/'  made  by  reaction  between  25  grains  of  HgCl2  and  a  pint 
of  lime-water. 

HgCl2  +  Ca(HO)2  =  HgO  +  CaCl2  +  H20 
Both  oxids  are  used  extensively  in  medicine. 
Experiment. — Make  lotio  nigra  and  lotio  flava  as  above  described. 

Aluminum. — A1203,  or  alumina,  is  found  native  in  hard 
crystalline  minerals,  and  is  made  commercially  from  bauxite  by 
the  action  of  H2S04  or  of  Na2C03.  It  is  a  light,  white,  odor- 
less, and  tasteless  powder,  little  acted  on  by  acids  or  alkalies. 
Native  oxids  are  very  hard. 

Tin. — SnO  is  a  brown  or  white  powder.  Sn02  is  a  fine, 
white  or  buff  powder,  used  as  a  polishing  agent  under  the  name 
of  putty  powder. 

Lead. — The  suboxid,  Pb20,  is  a  soft,  black  powder.  The 
official  monoxid  is  in  two  varieties:  massicot,  prepared  by  heat- 
ing the  carbonate  or  hydrate  to  low  redness,  and  litharge,  a 
by-product  in  desilvering  lead-ores.  Both  are  yellowish,  but 
litharge  is  more  inclined  to  red.  They  saponify  fixed  oils  and 
fats.  Litharge  has  extensive  use  in  the  manufacture  of  flint 
glass,  in  drying  paints,  glazing  earthenware,  and  sweetening 
liquors,  in  lead  plasters,  and  as  the  chief  source  of  other  Pb 
salts.  The  sesquioxid,  Pb203,  is  also  a  reddish-yellow  powder. 
Red  lead,  or  minium,  Pb304,  is  obtained  by  carefully  heating 
(at  300°)  litharge.  It  is  used  as  a  pigment  and  in  flint  glass 
and  cements.  The  peroxid  or  puce  oxid  is  a  chocolate-brown 
powder  used  as  an  oxidizer  and  left  as  a  residue  from  red  lead 


METALLIC,  OR  BASIC,  OXIDS.  137 

when  this  is  heated  with  HN03.     Oxids  of  Pb  are  sometimes 
used  to  color  artificial  teeth. 

Experiment. — Prove  double  composition  of  red  lead  by  adding  to 
a  little  in  a  test-tube  6  times  its  volume  of  dilute  HN03.  PbO  is  dis- 
solved, leaving  a  dark-brown  residue  of  PbO2. 

Bismuth.  —  The  only  oxid  of  interest  is  Bi203,  a  yellow 
fusible  powder,,  prepared  by  roasting  other  salts  of  Bi.  It  is 
employed  in  making  opera-glasses,  for  which  purpose  it  sur- 
passes Pb. 

Chromium. — Cr03  ("chromic  acid")  appears  in  brown-red 
needles,  blackening  temporarily  on  heating.  On  account  of 
its  great  avidity  for  H20,  it  is  escharotic,  and  is  used  in  1-per- 
cent, solution  as  a  hardening  agent.  It  is  an  energetic  labora- 
tory oxidizer,  and  hence  should  never  be  prescribed  with  oxidiz- 
able  substances. 

Experiment. — Pour  absolute  alcohol  on  a  few  crystals  of  Cr03,  or 
lay  a  crystal  of  CrO3  on  a  pledget  of  cotton  moistened  with  absolute 
alcohol.  Spontaneous  ignition  takes  place — more  rapidly  when  warmed. 

Experiment. — Mix  equal  parts  H,S04  and  saturated  solution  of 
KaCr207,  and  note  red  prisms  of  Cr03  separate  as  liquid  cools. 

K2Cr207  +  H2S04  =  K2S04  +  H2Cr04  +  CrO3 

Cr203  (chromic  oxid)  is  a  dark-green  powder  used  for  col- 
oring glass,  porcelain,  enamels,  and  artificial  teeth  (modifies 
yellow  of  Ti02). 

Manganese. — Mn02,  the.  black  oxid,  is  used  in  the  labora- 
tory in  the  preparation  of  0  and  Cl.  It  imparts  an  amethyst 
or  purple  color  to  glass  and  dental  frit,  and  is  utilized  to  re- 
move by  oxidation  the  green  color  (due  to  iron-sand)  of  com- 
mon glass.  It  is  the  usual  source  of  other  Mn  compounds,  and 
unites  with  stronger  bases  to  form  manganates. 

Iron. — Ferric  oxid,  Fe203,  is  obtained  as  a  residue  in  dis- 
tilling fuming  sulphuric  acid  from  green  vitriol.  It  is  a  dark- 
red  powder  used  in  paints,  and  as  a  polishing  agent  under  the 
names  jewelers'  rouge,  colcothar,  and  caput  mortuum.  Ferroso- 
ferric  oxid,  Fe304,  is  the  natural  black  magnetite  or  lodestone, 
and  is  the  chief  constituent  of  "blacksmiths7  scales/' 

Silver. — Argentous  oxid,  Ag40,  is  a  black  lustrous  mass 
obtained  by  heating  Ag3C6H507  to  100°  and  at  same  time  sub- 
jecting to  H.  Argentic  oxid,  Ag20,  is  produced  by  reaction  of 
hydroxids  on  AgN03.  It  is  a  heavy,  blackish,  amorphous, 
slightly  soluble,  oxidizing  powder.  Highly  explosive  crystals  of 
Berthollet's  fulminating  silver  are  produced  by  dissolving  Ag20 
in  strong  NH4HO  and  diluting  with  H20.  The  peroxid,  Ag962, 
is  even  stronger  as  an  oxidizer  than  Ag20. 


138  INORGANIC  CHEMISTRY. 

Gold. — Au20,  aurous  oxid,  is  a  dark-violet  powder;  Au203, 
auric  oxid,  a  dark-brown  powder.  Au203  and  Pt02  lose  their  0 
at  low  red  heat. 

Miscellaneous.  —  CoO  and  MO  are  both  green  powders. 
Os04  ("osmic  acid")  is  a  delicate  histologic  stain.  Oxids  of  Ce, 
Th,  and  Zr  are  used  for  the  mantle  of  Welsbach  burners. 

NON-METALLIC   OXIDS. 

These  are  gases,  liquids,,  or  solids  composed  of  0  united 
to  some  electronegative  element.  Many  of  them  are  termed 
anhydrids,  since  they  join  with  water  to  form  acids.  Some  of 
them,  as  As203,  are  improperly  termed  acids. 

Halogens. — Three  oxids  of  Cl  are  known:  namely,  mon- 
oxid,  C120;  trioxid,  C1203;  and  tetroxid,  or  peroxid,  C1204. 
They  are  all  heavy,  greenish-yellow  gases,  with  strong,  irri- 
tating odors,  and  easily  condensed  to  reddish  liquids.  In  com- 
bination with  H20  the  first  and  second  form,  respectively,  hypo- 
chlorous  and  chlorous  acids.  On  account  of  the  slight  affinity 
of  0  for  Cl,  they  are  very  unstable,  and  ignite  or  explode 
easily. 

Experiment.  To  Illustrate  One  Form  of  Spontaneous  Combustion. 
—To  a  little  KC1O3  in  a  beaker  add  a  few  drops  of  H2S04.  When  the 
beaker  is  about  filled  with  the  greenish  gas,  drop  into  it  a  small  piece 
of  tissue-paper  saturated  with  turpentine. 

No  oxids  of  Br  or  F  are  known.  The  only  oxid  of  I  is  the 
pentoxid,  I205.  This  is  a  white,  crystalline  powder,  very  sol- 
uble in  water,  with  which  it  forms  iodic  acid,  HI03. 

Sulphur. — Four  oxids  are  known;  sesquioxid,  S203;  dioxid, 
S02;  trioxid,  S03;  and  heptoxid,  S207.  The  first  and  last  are 
of  no  practical  interest.  S02  is  formed  whenever  S  is  burned 
in  air.  One  kg.  of  S  produces  100  liters  of  S02.  It  may  be 
made  pure  by  heating  together  S  and  H2S04. 

S  +  2H2S04  =  3S02  +  2H20 

Another  laboratory  method  is  to  heat  H2S04  with  C  or 
Cu.  S02  forms  a  large  percentage  of  volcanic  vapors,  and  is 
abundant  in  the  air  of  large  cities  from  combustion  of  coal 
in  stoves  and  furnaces.  It  is  a  colorless  gas  with  a  suffocating 
sulphurous  odor,  and  is  very  hygroscopic,  40  volumes  dissolving 
in  1  part  of  H20  at  20°. 

Experiment. — Invert  a  dry  tube  filled  with  SO2  over  a  vessel  of 
H2O,  and  note  rise  of  liquid  in  tube. 

It  is  neither  combustible  nor  a  supporter  of  combustion., 


NON-METALLIC  OXIDS.  139 

but  reduces  0  compounds  actively.  It  bleaches  straw,  wool, 
and  silk  in  the  presence  of  water,  by  combining  with  the  0  of 
H20,  leaving  H  free  to  unite  with  the  0  of  the  organic  coloring 
matter;  the  color  may  be  restored  by  neutralizing  with  an 
alkali. 

Experiment.  —  Place  some  fresh  flowers  on  a  tripod,  and  ignite  a 
little  S  beneath,  covering  the  whole  with  a  bell-jar.  The  flowers  are 
bleached,  but  may  have  their  color  restored  by  washing  with  a  dilute 
alkali  (removes  S02)  or  with  very  dilute  HNO3  (restores  O  removed  by 
80,). 

As  an  anhydrid  S02  decomposes  NH3,  ptomains,  sulphids,  and  H2S, 
and  kills  bacteria.  It  is  extensively  used  for  fumigation  of  sick-rooms 
and  in  preserving  meats.  Aside  from  its  odor,  S0?  is  detected  with  paper 
saturated  in  solution  of  KI03  and  starch,  which  turns  blue,  but  is 
bleached  by  excess  of  gas. 

2KI03  +  5S02  +  4H20  =  2KHS04  +  I2  +  3H2SO4 

S03  is  prepared  most  readily  from  fuming  Nordhausen 
acid  by  application  of  heat,  as  follows:  — 


S03  appears  in  long,  silky,  transparent  prisms,  and  is  used 
in  the  manufacture  of  alizarin  and  for  dissolving  indigo.  With 
H20  it  combines  energetically  to  form  H2S04. 

Nitrogen.  —  There  are  5  oxids  of  N:  namely,  N90,  N202 
(NO),  N203,  N204  (N02),  and  N205-  All  are  unstable  and 
easily  dissociated  by  heat.  They  are  formed  in  Nature  by  the 
passage  of  electricity  through  the  atmosphere. 

N20  (nitrous  oxid,  or  laughing-gas)  was  discovered  by 
Priestley  in  1772.  It  is  prepared  by  cautiously  heating  (be- 
tween 210°  and  250°)  NH4N03,  which  breaks  up  as  follows:— 

NH4N03  =  N20  +  2H20 

For  anesthetic  use  N20  should  be  purified  of  the  higher 
oxids  by  passing  the  gas  through  two  wash-bottles,  one  con- 
taining NaHO,  the  other  FeS04.  N20  is  a  colorless,  odorless 
gas  of  sweet  taste,  soluble  in  about  1  volume  of  H20.  It  is  a 
decided  disinfectant  and  a  supporter  of  combustion,  parting 
readily  with  its  0.  It  has  received  the  name  laughing-gas  be- 
cause of  the  exhilarating  effects  it  first  evokes  when  inhaled. 
N20  is  much  used  by  dentists  as  a  pleasant  and  safe  anesthetic 
for  short  operations.  It  is  kept  for  convenience  in  the  liquid 
state  (30  atmospheres  at  0°)  in  wrought-iron  cylinders,  vapor- 
izing as  soon  as  the  pressure  is  removed. 

Experiment.  —  Make  N2O  and  note  properties. 


140  INORGANIC  CHEMISTRY. 

Nitric  oxid,  1ST202,  is  prepared  by  the  reduction  of  HN03 
with  metals: — 

Experiment. — Pour  HNO3  on  Cu,  forming  N2O2,  a  colorless  gas, 
which  in  contact  with  the  O  of  air  becomes  N2O4:  an  oxidizing  agent 
characterized  by  red  fumes.  This  is  also  a  test  for  HN03. 

3Cu  +  8HNO3  =  3Cu  (N03)2  +  N2O2  -f-  4H20 

N203  is  a  dark-blue  liquid,  made  by  warming  HN03  with 
starch.  It  combines  directly  with  H20  to  form  HN02.  N205 
is  a  white,  crystalline  solid,  obtained  by  treating  dry  AgN03 
with  Cl.  It  has  a  strong  affinity  for  H00,  with  which  it  forms 
HNO, 

Phosphorus. — The  oxids  of  P,  P203  and  P205,  respectively, 
are  formed  by  the  slow  oxidation  and  by  the  rapid  combustion 
of  P.  The  former,  a  white  amorphous  powder  with  garlicky 
odor,  unites  with  H20  to  form  phosphorous  acid,  H2PH03,  the 
salts  of  which,  termed  phosphites,  are  of  no  medical  interest. 
The  white  fumes  of  P205  have  an  eager  affinity  for  H20,  form- 
ing with  it  metaphosphoric,  pyrophosphoric,  or  orthophosphoric 
acid,  according  as  1  molecule  of  the  gas  unites  with  1,  2,  or  3 
molecules  of  H20. 

Boron. — B203  is  generally  prepared  by  heating  boric  acid 
to  redness: — 

2H3B03  =  B203  +  3H20 

It  is  a  colorless,  vitreous  solid,  and  is  used  in  blow-pipe 
work  to  convert  nitrates,  carbonates,  and  other  salts  into 
borates. 

Silicon. — A  grain  of  sand  is,  chemically  speaking,  silica, 
silex,  or  oxid  of  silicon,  Si02,  of  which  there  are  three  varie- 
ties (two  crystalline,  one  amorphous)  mentioned  under  ores. 
It  is  very  abundant  in  rocks  and  soils,  and  is  found  in  traces 
in  all  natural  waters.  Silica  gives  stiffness  to  stalks  of  grain 
and  grass,  and  is  present  in  the  blood,  hair,  and  bones  of  mam- 
mals. In  the  "petrified  wood"  found  in  Colorado  and  Arizona 
the  C  of  former  submerged  forest-trees  has  been  replaced  by 
Si02.  Quartz  is  soluble  only  in  HF.  The  other  varieties  of 
Si02  are  also  soluble  in  boiling  solutions  of  alkaline  hydroxids 
or  carbonates. 

All  forms  of  silica  find  extensive  industrial  uses,  partic- 
ularly in  the  manufacture  of  glass,  pottery,  and  artificial  teeth. 
Agate  is  used  for  the  hardest  mortars.  Kieselguhr,  or  diatom- 
aceous  earth,  is  an  amorphous  form  of  Si02  used  as  an  ab- 
sorbent for  nitroglycerin  in  the  production  of  dynamite.  A 


NON-METALLIC  OXIDS.  141 

little  sand  sprinkled  on  the  hot  iron  aids  the  process  of  welding 
by  forming  with  the  surface  oxid  a  fusible  slag. 

Experiment. — Heat  before  blow-pipe  a  bead  of  microcosmic  salt 
touched  with  a  minute  grain  of  sand,  and  note  "silica  skeleton"  formed 
in  bead. 

Carbon. — Carbon  monoxid,  CO,  is  a  colorless,  almost  odor- 
less, gaseous,  unsaturated  compound  produced  by  incomplete 
combustion  of  C  or  carbonaceous  substances  in  a  deficient  sup- 
ply of  0.  It  is  formed  in  base-burner  stoves  at  night,  when  but 
little  air  is  allowed  to  enter  the  stove;  also  when  there  is  a 
defective  draught.  The  gas  burns  with  a  bluish  flame,  form- 
ing C02.  It  is  an  active  reducing  agent,  and  diffuses  readily 
through  red-hot  cast-iron:  stoves  and  furnaces,  for  instance. 

Experiment. — Make  CO  by  heating  together  equal  parts  of  wood- 
charcoal  and  CuO  in  a  side-necked  test-tube  with  delivery-tube,  collect- 
ing gas  over  H,0. 

Experiment. — Make  CO  by  warming  1  part  K4FeCy8  with  9  parts  of 
H2SO4. 

K4Fe(CN)6  +  GH2S04  +  6H2O  =  2K2S04  +  3(NH4)2SO4  +  FeSO4  +  6CO 

C02  was  the  first  gas  to  be  separated  from  air,  this  event 
taking  place  in  the  seventeenth  century.  Pure  country  air 
contains  4  parts  of  C02,  by  volume,  in  10,000.  The  amount  in 
the  atmosphere  is  greatest  at  night.  More  than  7  parts  in 
10,000  are  oppressive  and  injurious.  This  gas  is  also  present 
in  all  natural  waters,  being  most  abundant  in  certain  mineral 
springs;  also  in  beer-  and  wine-  vats;  and  is  the  "choke-damp" 
of  wells  and  mines.  It  is  produced  by  burning  C  with  a  free 
supply  of  air;  also  by  respiration  (expired  air  contains  4  to  5 
per  cent.),  ordinary  fermentation,  and  the  oxidation  and  decay 
of  organic  matter.  An  ordinary  lamp  sets  free  in  burning  as 
much  C02  as  an  adult  person;  a  gas-jet  two  to  four  times  as 
much.  Artificially  C02  is  prepared  by  action  of  any  common 
acid  (mineral  ones  usually  employed)  on  a  carbonate. 

Experiment. — Make  CO2  by  treating  Na2CO3  with  HC1,  and  test  gas 
by  passing  into  lime-water.  Notice  that  the  lime-water  becomes  at  first 
cloudy,  and  then  again  when  surcharged  clear,  owing  to  the  formation 
of  the  more  soluble  acid  carbonate  of  Ca. 

C02  is  a  colorless  gas  with  a  sharp  taste  and  acid  smell.  It 
turns  blue  litmus  purple  or  wine-red,  the  blue  color  being  re- 
stored by  heat.  Although  it  is  half  again  as  heavy  as  air  at 
the  same  temperature,  the  foulest  air  in  a  living-room  is  next 
the  ceiling,  because  of  the  warming  by  the  blood  of  the  exhaled 
gas,  and  also  since  ventilation  is  usually  less  perfect  at  the  top 


142  INORGANIC  CHEMISTRY. 

of  the  room.    In  wells  and  mines  the  gas  is  most  abundant  at 
and  near  the  bottom. 

Experiment.—  Float  soap-bubbles  on  C02  in  a  wide  vessel. 

C02  is  soluble  in  1  volume  H20  with  chemic  union,  form- 
ing H2C03.  The  popular  beverage  known  as  soda-water  con- 
tains 5  volumes  of  this  gas  to  1  of  water.  The  gas  is  forced 
in  under  pressure,  which  is  relieved  for  each  glass  of  the  liquid 
drawn,  with  consequent  effervescence.  C02  for  soda-water  is 
now  sold  liquefied  by  a  pressure  of  40  atmospheres  in  steel 
cylinders.  On  evaporation  this  liquid  produces  intense  cold 
(  —  110°).  Many  mineral  waters  are  artificially  carbonated. 
The  gas  has  been  frozen  into  a  snow-white  solid. 

CO,,  being  an  acid  gas,  has  marked  affinity  for  alkaline 
solutions. 

Experiment.  —  Show  absorption  of  C02  by  alkaline  hydroxids  oy 
adding  to  test-tube  or  jar  of  gas  a  solution  of  KHO  and  shaking  well, 
then  remove  stopper  under  water,  and  the  latter  rushes  in  to  take  the 
place  of  absorbed  gas. 

C02  is  neither  combustible  nor  a  supporter  of  combustion, 
and  is  used  to  some  extent  as  the  "chemic  fire-extinguisher/' 

Experiment.  —  Invert  candle  into  jar  of  C02. 

Experiment.—  Light  candle  again  and  place  under  bell-jar  filled 
with  air.  When  C02  amounts  to  12  per  cent,  the  light  goes  out. 

Hydrogen.  —  Hydrogen  peroxid,  H202,  is  a  colorless,  syrupy 
liquid  (sp.  gr.,  1.45),  with  a  sharp  odor  and  tingling,  metallic 
taste.  It  is  very  soluble  in  ether  and  water.  It  is  usually 
prepared  as  per  the  following  equation:  — 

3Ba02  +  2H3P04  =  Ba3(P04)2  +  3II20 


22 


or  more  easily  by  passing  C02  into  aqueous  suspension  of  Ba02. 
Other  acids  may  be  used.  It  is  concentrated  by  evaporating 
at  not  above  60°.  It  corrodes  metals  and  decomposes  readily 
into  H20  and  nascent  or  atomic  0,  on  exposure  to  air  and  sun- 
light, and  especially  when  heated;  hence  it  is  a  strong  oxidizer, 
and  should  be  kept  in  a  cool  place  well  stoppered. 

Experiment.—  Prove  oxidizing  action  of  H202:  To  a  little  HA 
solution  add  a  drop  each  of  K,CrO4  and  H2S04  and  a  little  ether,  and' 
shake.  A  blue  color,  due  to  perchromic  acid,  results. 

On  account  of  its  unstable  character,  H202  should  not  be 
prescribed  with  any  other  substance  than  H20.  The  ordinary 


NON-METALLIC  OXIDS.  143 

solutions  of  this  compound  vary  in  strength  from  1  to  10  vol- 
umes of  available  0,  or  up  to  3  per  cent.,  by  weight,  of  pure 
dioxid.  Boric  acid,  glycerin,  and  traces  of  free  acids  are  of 
value  as  preservatives  for  these  preparations.  The  peroxid  is 
much  employed  for  bleaching  wool,  teeth,  and  hair  (combined 
with  weak  alkalies)  and  for  cleansing  (brightens  old  books  and 
pictures)  and  antiseptic  purposes.  It  is  particularly  useful  in 
treating  abscess  cavities;  the  chemic  action  that  ensues  drives 
out  the  pus  with  effervescence.  It  also  effervesces  with  blood, 
saliva,  and  other  organic  substances. 

Special  Test. — H2O2  gives  a  blue  color  with  a  solution  containing 
starch,  KI,  and  FeSO4. 

2KI  +  H202  =  2KHO  +  I2 

Arsenic. — As203  (arsenous  oxid,  white  arsenic)  was  known 
as  early  as  the  eighth  century.  It  is  the  "arsenic  bloom"  of 
miners,  and  is  obtained  as  a  side-product  in  roasting  ores  con- 
taining As.  The  powder  has  a  sweetish,  disagreeable,  metallic 
taste.  It  volatilizes  at  218°.  Its  solubility  varies  with  the 
physic  condition,  the  amorphous,  glassy  variety  requiring  but 
30  parts  of  cold  water,  whereas  the  opaque,  crystalline  form  is 
dissolved  by  not  less  than  80  parts.  As203,  though  heavier 
than  H20,  floats  partly  on  this  fluid,  owing  to  repulsion.  The 
solubility  of  either  variety  is  greatly  increased  by  the  addition 
of  a  little  HC1  or  alkali.  It  is  also  soluble  in  5  parts  of  glyc- 
erin. It  is  much  used  in  medicine  and  dentistry;  in  embalm- 
ing, taxidermy,  manufacture  of  green  colors  and  opaque  white 
glass;  in  calico-printing,  and  as  the  source  of  all  As  compounds. 
As203  is  used  largely  in  dentistry  as  a  devitalizing  agent,  usu- 
ally mixed  with  morphin  or  cocain  and  creasote,  oil  of  cloves 
or  phenol,  sealed  in  with  gutta-percha  or  other  protective.  It 
"kills  the  nerve"  by  causing  such  an  irritant  congestion  of  the 
pulp  as  to  lead  to  strangulation  of  the  vessels  at  the  apex  of 
the  tooth.  It  is  used  by  "cancer  specialists"  as  an  escharotic 
to  "eat  out"  these  tumors.  Liquor  acidi  arseniosi  is  a  1-per- 
cent, solution  of  As203  in  water  containing  5  per  cent,  of  dilute 
HC1. 

As205  (arsenic  oxid)  is  of  little  medical  interest;  it  is 
usually  prepared  by  warming  As203  with  HN~03.  Both  this 
oxid  and  arsenic  acid  are  used  as  oxidizing  agents  in  the 
preparation  of  anilin  colors. 

Antimony. — The  trioxid  is  a  heavy,  light-gray  powder,  in- 
soluble in  HN03,  but  readily  dissolved  by  HC1,  warm  H2C4H406, 
or  KHC4H406.  It  is  used  in  preparing  tartar  emetic  and  as  a 
substitute  for  white  lead. 


144  INORGANIC  CHEMISTRY. 


INORGANIC  ACIDS. 

These  are  strongly  acid,,  as  a  rule,  and  attack  most  metals, 
forming  salts,  with  evolution  of  H. 


HYDRO-ACIDS. 

These  are  solutions  of  colorless,  acid  gases  in  H20.  They 
have  a  sharp,  irritating  odor.  Their  vapors  redden  moistened 
blue  litmus-paper.  They  are  generally  prepared  by  treating 
the  appropriate  salt  with  H2S04  or  H3P04.  They  should  leave 
no  residue  on  evaporating  to  dryness.  Their  tests  are,  in  gen- 
eral, the  same  as  for  their  salts,  but  a  few  special  ones  are 
given  below. 

HC1  is  the  most  important  of  the  hydro-acids.  In  the  pure 
state  it  is  a  non-combustible  gas  one-fourth  heavier  than  air. 
It  is  found  naturally  in  the  atmosphere,  especially  near  vol- 
canoes and  chemic  works,  and  also  in  the  human  gastric  juice 
(0.1  or  0.2  per  cent.).  HC1  is  usually  manufactured  from  com- 
mon salt  by  the  chemic  action  thereon  of  H2S04,  with  the  aid 
of  heat. 

2NaCl  +  H2S04  =  Na2S04  +  2HC1 

Experiment.— In  a  suitable  flask  place  Va  inch  dry  NaCl,  fill  flask 
1/s  full  with  dilute  H2S04,  heat  till  boiling  hard,  then  pass  gas  into  H.,0 
in  beaker.  It  may  be  purified  Dy  redistillation. 

On  a  large  scale  HC1  is  a  leading  by-product  in  the  manu- 
facture of  soda.  HC1  causes  a  red  stain  on  dark  cloths,  readily 
removed  by  NTI4HO. 

HC1  gas  is  extremely  soluble  in  H20,  1  volume  of  the  latter 
at  0°  dissolving  503  volumes,  or  82  per  cent.,  by  weight,  of  the 
former.  This  solution  has  bleaching  and  antiseptic  properties, 
and  is  much  used  as  a  reagent. 

Experiment. — Show  intense  avidity  of  HC1  gas  for  H2O  by  opening 
a  test-tube  of  the  gas  under  water,  tinged  with  blue  litmus.  Explain 
color-change  and  why  the  water  rises  in  the  tube. 

The  official  HC1  contains  32  per  cent.,  by  weight,  of  the 
gas,  and  has  a  sp.  gr.  of  1.16.  The  dilute  acid  is  of  10-per-cent. 
strength;  sp.  gr.,  1.05.  The  yellow  color  of  common  HC1  is 
due  chiefly  to  Fe  compounds.  HC1  is  used  extensively  in  medi- 
cine, particularly  when  there  is  a  deficiency  of  the  acid  in  the 
gastric  juice.  In  manufacturing  chemistry  it  is  employed  in 
the  preparation  of  chlorates,  chloroform,  and  bleaching  powder. 

Nitrohydrochloric  acid  (aqua  regia)  is  made  by  mixing  40 


INORGANIC  ACIDS.  145 

c.c.  HN"03  with  180  c.c.  HC1,  letting  them  stand  for  a  week  or 
two.    The  reactions  between  the  two  acids  are  as  follows: — 

HN03  +  3HC1  =  NOC1  +  2H20  +  201 
HN03  +  3H01  =  NOC12  +  2H20  +  Cl 

It  will  be  seen  that  HN03  oxidizes  the  H  of  both  acids. 
The  solvent  power  of  aqua  regia  on  Au  and  Pt  depends  on  its 
free  Cl  and  the  chloronitrous  and  chloronitric  gases,  which  give 
up  their  Cl  very  easily.  The  official  dilute  acid  is  made  by 
diluting  the  strong  acid  with  H20  up  to  a  liter. 

Special  Test  for  HC1. — Dense,  white  fumes  (NH4C1)  appear  when 
a  glass  rod  dipped  in  NH4HO  is  held  over  mouth  of  container. 

HBr  can  be  prepared  from  any  bromid  (usually  KBr)  by 
treating  it  with  concentrated  H2S04.  The  dilute  HBr  of  the 
United  States  Pharmacopeia  contains  10  per  cent.,  by  weight, 
of  the  absolute  acid  gas  dissolved  in  distilled  H20,  and  has  a 
sp.  gr.  of  1.077.  Quinin  is  sometimes  administered  in  dilute 
HBr,  the  Br  of  the  acid  neutralizing  the  hyperemic  effect  of 
the  alkaloid  on  the  inner  ear. 

Special  Test  for  HBr. — Reddish  fumes  when  heated  with  strong 
H2S04. 

The  official  syrup  of  HI  is  of  1-per-cent.  strength;  the 
sugar  serves  to  prevent  actinic  decomposition.  HI  readily 
parts  with  its  H  and  is  therefore  an  active  reducing  agent,  being 
used  in  photography. 

Special  Test  for  HI. — Gas  gives  brown  color  to  paper  moistened 
with  Cl  water. 

The  only  important  artificial  compound  of  F  is  HF,  pre- 
pared by  gently  heating  in  a  leaden  dish  CaF2,  treated  with  an 
excess  of  H2S04.  The  HF  gas  thus  formed  combines  with  the 
silica  of  the  glass,  owing  to  which  fact  it  has  been  used  more 
than  two  hundred  years  for  etching  glass. 

Experiment. — Show  action  of  fresh  HF  on  glass  covered  with  a 
paraffin  coating  in  which  a  design  has  been  traced  down  to  the  glass. 

An  aqueous  solution  of  HF  is  used  for  marking  thermom- 
eters and  glass  measures.  It  is  very  volatile  and  caustic,  pro- 
ducing painful  and  slow-healing  ulcers  if  allowed  to  come  in 
contact  with  the  skin.  The  local  effect  of  the  acid  can  be  neu- 
tralized to  some  extent  by  applying  NH4HO  or  some  other  weak 
base.  The  dilute  acid  is  stored  in  gutta-percha  bottles. 

H2S  is  a  sweet-tasting,  foul-smelling  gas  derived  from  the 

10 


146  INORGANIC  CHEMISTRY. 

putrefaction  of  organic  bodies  containing  S  (eggs,  for  instance), 
and  also  present  in  many  mineral  waters.  It  is  the  chief  con- 
stituent of  sewer-gas,  and  burns  in  air  with  a  blue  flame.  H2S 
is  prepared  for  laboratory  use  by  treating  FeS  with  H2S04  (1 
to  6).  It  rapidly  decomposes  on  exposure  to  air  into  H  and  S, 
which  accounts  for  the  S  deposits  on  the  edges  of  sulphureted 
springs.  This  gas  tarnishes  silverware,  and  also  combines  with 
many  other  metals,  giving  precipitates  with  characteristic 
colors. 

Experiment. — Show  reaction  of  H2S  on  solutions  of  Pb,  Sb,  As,  Sn, 
and  Zn  salts. 

Aside  from  the  odor,  we  may  detect  very  small  quantities 
of  the  gas  by  saturating  a  piece  of  white  filter-paper  with  lead 
acetate  solution,  and  exposing  it  for  some  hours  where  we  have 
reason  to  suspect  the  gas  is  escaping.  The  sulphids,  or  salts 
of  H2S,  constitute  the  most  common  ores  of  the  more  common 
metals.  The  black  stools  often  noticed  after  taking  Fe,  Bi,  or 
Pb  salts  are  due  simply  to  the  union  of  the  medicine  with  the 
H2S  formed  by  putrefaction  in  the  alimentary  tract.  Patho- 
logically H2S  is  present  in  fetid  abscesses,  and  the  odor  of  the 
gas  in  the  urine  in  some  cases  aids  to  determine  the  rupture 
of  an  internal  abscess  into  the  urinary  tract  or  a  fistulous  com- 
munication between  the  bladder  and  the  rectum. 

Hydrofluosilicic  acid,  H2SiF6,  is  known  only  in  solution. 
It  dissolves  metals,  forming  silicofluorids,  which  are  pptd.  by 
K  salts  as  gelatinous  K2SiF6. 

Chloric,  perchloric,  hypochlorous,  hypobromous,  bromlc, 
iodic,  periodic,  cyanic,  thiocyanic,  ferrocyanic,  ferricyanic,  man- 
ganic, permanganic,  chromic,  stannic,  antimonic,  and  silicic 
acids  have  no  practical  interest. 

THIO-ACIDS. 

The  most  important  and  most  powerful  of  the  mineral 
acids  is  H2S04,  or  sulphuric  acid.  It  occurs  free  in  the  atmos- 
phere near  chemic  works  and  in  volcanic  springs  and  rivers 
(Andes).  The  principal  sources  of  this  acid  are  S  and  FeS2. 
The  process  of  manufacture  of  H2S04  commonly  depends  on 
the  oxidation  of  S02  into  S03  in  the  presence  of  H20  as  steam. 
The  intermediate  agent  in  oxidation  is  N204,  formed  by  treat- 
ing NaN03  with  H2S04.  This  gas,  N204.  gives  up  two  atoms 
of  0  to  S02,  and  is  reduced  to  N202,  which  again  takes  up  the 
0  from  the  air  at  hand,  and  so  the  reaction  goes  on  indefinitely 
as  long  as  the  fumes  of  burning  S  or  FeS2  are  passed  into  the 
chamber  along  with  steam  and  air. 


INORGANIC  ACIDS. 


147 


2S02  +  N204 '+  2H20  =  2H2S04  +  N202 

The  acid  thus  formed  is  purified  by  distilling,  and  is  col- 
lected in  leaden  pans,  concentration  being  completed  in  glass 
or  Pt  vessels. 

Experiment. — Make  H2S04  by  carefully  heating  a  little  S  and 
KC1O3  in  a  test-tube  till  they  ignite.  Add  H2O  and  test  for  acid  as 
under  "Sulphates." 


Fig.  26.— Preparation  of  Sulphuric  Acid. 

H2S04  is  a  colorless,  odorless,  oily,  corrosive  liquid  of  96- 
per-cent.  strength;  sp.  gr.,  1.84.  The  official  acid  is  92  1/2  per 
cent.;  sp.  gr.,  1.835.  The  aromatic  sulphuric  acid  contains  also 
alcohol  and  aromatics,  and  is  of  20-per-cent.  strength. 

H2S04  is  intensely  avid  of  H20,  and  to  this  is  due,  in  part, 
the  characteristic  effects  of  the  acid  on  organic  substances. 

Experiment. — Show  charring  action  of  strong  H2SO4  on  white 
sugar.  On  account  of  its  hygroscopic  properties,  H2SO4  is  much  em- 
ployed in  desiccators.  It  combines  with  2H2O  to  form  HP,SO6  (orthosul- 
phuric  acid),  the  reaction  being  attended  by  considerable  heat  and  by 
8-per-cent.  reduction  in  volume.  When  mixed  with  H._,O  the  acid  should 
be  added  gradually  to  the  water,  and  not  the  water  to  the  acid,  as  in 


148  INOEGANIC  CHEMISTRY. 

the  latter  event  the  acid  steam  that  is  thrown  off  may  scald  a  person. 
Dilute  H2SO4  attacks  metals  more  rapidly  than  the  strong  acid,  since 
in  the  latter  case  the  chemic  action  is  soon  hindered  by  the  coating  of 
sulphate  that  forms  on  the  metal.  The  reddish-brown  stain  produced 
by  this  acid  on  dark  textiles  disappears  on  adding  NH4HO. 

H2S04  is  more  extensively  employed  industrially  than  any 
other  chemic  compound.  A  million  tons  of  the  acid  are  con- 
sumed annually  in  England  in  the  Leblanc  soda-process.  Other 
uses  of  this  acid  are  in  the  manufacture  of  HN03,  of  ether, 
nitroglycerin,  gun-cotton,  parchment-paper,  and  fertilizers,  the 
production  of  C02  from  marble-dust,  the  conversion  of  starch 
into  glucose,  the  refining  of  petroleum,  the  separation  of  Ag 
and  Au,  drying  of  gases  and  precipitates,  and  in  the  dental 
laboratory  the  dilute  acid  is  employed  as  a  "pickle"  for  clean- 
ing metallic  plates  before  and  after  soldering. 

Sulphurous  acid,  H2S03,  is  formed  by  passing  S02  into 
H20,  or  by  the  reducing  action  of  S  or  charcoal  on  H2S04. 

Experiment. — Make  H2S03  by  placing  10  or  20  gm.  charcoal  in  a 
flask,  covering  with  H2S04  and  applying  heat,  passing  gas  through  wash- 
bottle  and  collecting  in  water. 

Sulphurous  acid  is  a  colorless  liquid;  sp.  gr.,  1.035;  of  not 
less  than  6.4-per-cent.  strength,  by  weight,  with  an  acid,  sul- 
phurous taste  and  smell.  It  first  reddens,  then  decolorizes, 
litmus;  and  is  used  to  some  extent  as  a  bleaching  and  disin- 
fecting agent.  Decolorization  of  an  I  solution  with  this  acid 
depends  on  the  conversion  of  I  into  HI  as  follows: — 

H2S03  +  I2  +  H20  =  H2S04  +  2HI 

Experiment. — Show  bleaching  effect  of  H2S03  on  permanganate 
solution. 

Both  the  acid  and  its  salts  are  detected  by  giving  a  light- 
colored  ppt.  with  Ag,  Pb,  or  Hg,  which  blackens  on  heating, 
owing  to  the  change  of  sulphite  into  sulphid. 

The  fuming  Nordhausen  acid,  H2S207,  is  a  thick,  oily 
liquid  obtained  by  roasting  basic  pyrites  (Fe2S209)  or  by  pass- 
ing SO,  (from  heated  FeSOJ  into  H2S04.  This  acid  is  a  solvent 
for  indigo. 

Hyposulphuric  acid,  H2S02,  is  prepared  by  the  reducing 
action  of  Zn  on  H2S03.  It  is  a  yellow,  unstable  liquid;  a  pow- 
erful bleaching  agent;  and  it  ppts.  the  metals  from  solutions 
of  their  salts,  as  in  the  following  reaction: — 

HgCl2  +  H2S02  +  H20  =  Hg  +  2HC1  +  H2S08 
Experiment. — Show  reaction  represented  by  above  equation. 


INORGANIC  ACIDS.  149 

Among  other  sulphur  acids  of  little  importance  may  be 
mentioned  H2S203  (thiosulphuric),  H2S206  (dithionic),  H2S306 
(trithionic),  H2S406  (tetrathionic),  H2S506  (pentathionic),  and 
H2S208  (persulphuric).  H2S  (hydrosulphuric  acid)  has  been 
discussed  already  under  "Hydro-acids." 

CARBONIC   ACID. 

H2C03  is  not  known  in  a  free  state,  since  it  splits  up  into 
C02  and  H20  as  soon  as  formed. 


BORIC,   OR   BORACIC,  ACID. 

H3B03  is  obtained  by  evaporation  from  the  steam-jets  or 
fumeroles  in  the  volcanic  regions  of  Tuscany.  In  the  United 
States  it  is  also  prepared  by  treating  borax  with  HC1.  The 
pure  acid  is  a  white  powder,  unctuous,  odorless,  and  nearly 
tasteless.  It  is  soluble  in  26  water,  15  alcohol,  and  10  glycerin. 

Special  Tests. — The  solution  in  alcohol  burns  with  a  green-tinged 
flame.  Dissolve  in  hot  water  and  dip  turmeric  paper  in  solution.  Color 
of  paper  unchanged,  but  on  drying  becomes  brown-red,  turning  green 
on  moistening  with  KHO. 

Boric  acid  is  a  valuable  non-toxic  and  non-irritating  anti- 
septic, which  can  be  used  with  safety  in  any  part  of  the  body. 
It  is  often  added  to  alkaloidal  substances — e.g.,  cocain — to  pre- 
vent decomposition. 

Boroglycerid  is  a  thick,  syrupy  liquid,  made  by  heating 
together  1  part  of  the  acid  with  1 1/2  parts  of  glycerin.  It  is 
an  antiseptic  depletant.  H3B03  and  boroglycerid  are  each  used 
in  combination  with  Na2S03  for  bleaching  discolored  teeth. 

When  heated  to  100°,  H3B03  loses  H20  and  becomes 
metaboric  acid,  HB02,  which  on  further  heating  (140°)  is  con- 
verted into  tetraboric  acid,  H2B407,  of  which  borax  is  the 
principal  salt. 

NITRO-ACIDS. 

True  nitrous  acid,  HN02,  is  a  very  unstable  blue  liquid, 
made  by  passing  N203  into  ice-water,  or  by  warming  HN03 
with  starch-water. 

Nitric  acid,  HN03,  is  generally  prepared  commercially  by 
the  action  of  H2S04  on  KN"03.  The  pure  acid  is  a  colorless, 
fuming,  suffocative,  and  very  corrosive  liquid;  sp.  gr.,  1.52 
(U.  S.  P.,  1.42);  of  68-per-cent.  strength.  The  dilute  acid  is  of 
10-per-cent.  strength;  sp.  gr.,  1.057. 


150  INORGANIC  CHEMISTRY. 

Experiment. — Show  corrosive  action  and  yellow  color  (xantho- 
proteic  test)  of  HN03  on  black,  woolen  cloth.  The  same  color  is  noticed 
on  the  nails,  skin,  or  any  nitrogenous  substance. 

It  parts  easily  with  some  of  its  0,  and  is,  hence,  a  strong 
oxidizing  agent,  for  which  reason  it  should  never  be  prescribed 
with  sugar,  alcohol,  glycerin,  oils,  or  other  combustible  sub- 
stances. 

Experiment. — Pour  HNO3  on  warmed  turpentine  in  beaker,  and 
note  spontaneous  combustion. 

Most  metals  dissolve  in  strong  HN03,  forming  nitrates. 
Au,  Pt,  and  Ir  do  not  so  dissolve,  and  Sb  and  Sn  oxidize,  but 
are  not  dissolved.  These  are  dissolved  by  aqua  regia,  made  by 
mixing  together  4  HC1  and  1  HN"03.  Fe,  Pb,  and  Ag  dissolve 
in  dilute,  but  not  in  strong,  HN03.  When  immersed  in  the 
latter  a  piece  of  Fe  is  rendered  passive,  not  dissolving  now  in 
the  dilute  acid  until  some  other  metal,  as  Pt,  is  added  to  break 
the  spell. 

The  fuming  acid  is  brownish  red  on  account  of  containing 

in  solution.  HN03  on  exposure  to  light  and  air  decom- 
poses into  a  yellowish  liquid,  nitroso-nitric  acid,  which  contains 
NO  and  is  commercially  known  as  nitrous  acid. 

HN03  is  used  internally  (diluted)  and  as  a  caustic;  also 
in  refining  metals  and  engraving  Cu  plates,  and  in  the  manu- 
facture of  gun-cotton,  nitroglycerin,  and  anilin  dyes. 

Test  for  Strong  Acid. — Red  fumes  of  N204  evolved  on  heating  with 
Cu  foil  or  filings.  Green  cupric  nitrate  is  formed,  H  is  evolved,  and 
partly  deoxidizes  some  of  HN03  (HN03  +  3H  =  2H2O  +  NO),  forming 
NO  (N2O2),  which  takes  up  02  from  air  and  becomes  colored. 

Test  for  Dilute  Acid. — Add  some  FeSO4  to  suspected  liquid,  and 
slide  under  mixture  strong  H2SO4.  A  brownish  or  black  ring  at  point 
of  contact  proves  presence  of  HNO3. 

PHOSPHORUS  ACIDS. 

Orthophosphoric  acid,  H3P04,  is  prepared  by  boiling  P 
with  dilute  HN03  or  by  treating  any  phosphate  with  H2S04. 
That  used  in  dental  cements  is  prepared  by  dissolving  HP03 
in  warm  water  and  evaporating  to  a  syrupy  consistence.  The 
United  States  Pharmacopeia  preparation  is  a  colorless,  odor- 
less, syrupy  liquid  containing  at  least  85  per  cent,  of  absolute 
acid;  sp.  gr.,  1.7.  The  dilute  formula  contains  10  per  cent,  of 
absolute  acid.  H3P04  is  a  tribasic  acid,  forming  normal,  acid, 
and  double  salts.  It  is  not  volatilized  by  red  heat.  Evaporat- 
ing spontaneously,  it  yields  prismatic  crystals. 

When  H3P04  is  heated  to  about  200°  it  loses  water  and  is 
converted  into  pyrophosphoric  acid,  H4P207. 


INORGANIC  ACIDS.  151 

2H3P04  —  H20  =  H4P207 

When  H4P207  is  heated  nearly  to  redness,  it  is  also 
dehydrated  into  glacial  phosphoric  or  metaphosphoric  acid, 
HP03:  a  colorless,  glassy  solid.  Both  this  acid  and  H4P207 
are  corrosive  and  paralyzant  poisons,  acting  especially  on  the 
innervation  of  the  heart. 

Hypophosphorous  acid,  HPH202,  is  a  white,  crystalline 
substance,  obtained  by  decomposing  Ca(PH202)2  with  oxalic 
acid.  It  is  a  strong  deoxidizer.  The  dilute  acid  is  of  10-per- 
cent, strength.  On  exposure  to  air  it  takes  up  0  and  becomes 
the  colorless  liquid  phosphorous  acid,  H3P03.  This,  in  turn, 
is  oxidized  into  H3P04. 

Differential  Tests. — H3PO4  gives  a  yellow  ppt.  of  Ag3P04  with 
argent-ammonium  hydrate:  soluble  both  in  HN03  and  NH4HO.  Ortho- 
phosphoric  acid  gives  a  yellow  ppt.  with  AgN03;  meta-  and  pyro-  white. 
Pyrophosphoric  acid  gives  white  ppt.  with  MgSO4;  metaphosphoric  acid 
none  at  all. 

ARSENOTTS   AND  ARSENIC  ACIDS. 

H3As03  is  not  known  in  the  free  state,  but  exists  in  solu- 
tions of  As203.  H3As04  appears  in  white,  deliquescent  crys- 
tals, which  are  strongly  corrosive  and  blister  the  skin.  Its 
solutions  give  a  brick-red  ppt.  of  Ag3As04  on  adding  argent- 
ammonium  hydrate. 

HYDROXIDS. 

These  may  be  regarded  as  H20  in  which  one-half  of  its 
H  is  replaced  by  a  metal.  They  are  mostly  white,  crystalline, 
deliquescent  solids  (except  NH4HO)  with  strongly  alkaline  re- 
action and  caustic,  alkaline  taste.  They  are  commonly  purified 
by  dissolving  in  alcohol  and  decanting.  Commercial  prepara- 
tions contain  from  10  to  25  per  cent.  H20.  Hydroxids  of  the 
alkaline  metals  and  alkaline  earths  are  more  or  less  soluble  in 
H20;  all  others  insoluble.  Solution  produces  considerable 
heat  on  account  of  taking  up  water  of  crystallization.  The 
soluble  hydroxids  are  recognized  by  melting  and  volatilizing 
unchanged,  by  dissolving  in  HC1  without  odor  or  effervescence, 
and  by  giving  a  dark-brown  ppt.  of  Ag20  with  AgN03.  The 
insoluble  ones  give  off  steam  when  heated  in  a  nearly  hori- 
zontal, dry  test-tube,  leaving  a  residue  of  oxid. 

KHO  is  soluble  in  0.5  H,0  or  2  alcohol;  the  alcoholic  so- 
lution soon  turns  dark  yellow  to  brown,  forming,  in  presence 
of  air,  aldehyd  and  acetic  acid.  Official  liquor  potassse  is  5 
per  cent,  in  strength,  with  sp.  gr.  of  1.036.  Potassa  cum  calce 


152  INORGANIC  CHEMISTRY. 

is  a  caustic  paste  composed  of  equal  parts  of  KHO  and  CaO. 
Kobinson's  remedy  contains  equal  parts  of  KHO  and  carbolic 
acid.  NaHO  is  soluble  in  1.7  H20  and  is  very  soluble  in  alco- 
hol. Liquor  sodas  contains  about  5  per  cent.  NaHO,  and  has 
a  sp.  gr.  of  1.059.  Crude  NaHO  has  extensive  use  in  soap- 
making. 

Ammonia,  NH3  is  a  gaseous  compound  present  in  the 
atmosphere  in  minute  amounts  in  combination  with  nitrous, 
nitric,,  and  carbonic  acids.  It  is  a  product  of  organic  decom- 
position and  dry  distillation;  soft  coal  yields  about  2  per  cent. 
Its  chief  source  at  present  is  the  ammoniacal  liquors  formed 
during  the  manufacture  of  illuminating  gas.  The  gas  is  freed 
from  its  compounds  in  this  liquid  by  distilling  with  lime  and 
collecting  in  water.  NH3  is  colorless,  and  has  a  sharp,  suf- 
focating smell.  When  mixed  with  0  it  ignites,  forming  N", 
H20,  and  HN03.  It  is  liquefied  by  freezing  mixtures  at  — 40° 
or  by  a  pressure  of  6  or  7  atmospheres.  The  liquid  boils  at 
—  38.5°,  absorbing  much  heat;  hence  it  is  employed  in  cooling- 
apparatuses  and  in  making  ice.  Water  dissolves  600  volumes  of 
the  gas  at  ordinary  temperatures,  forming  NH4HO.  This 
hydroxid  readily  parts  with  its  NH3,  especially  on  warming, 
and  hence  is  known  as  the  volatile  alkali. 

Experiment. — With  red  litmus-paper  moistened  with  H20  and  held 
in  neck  of  bottle,  show  volatility  of  NH4HO,  and  notice  that  red  color 
is  restored  on  drying. 

NH4HO  is  official  in  two  strengths:  aqua  ammonias  (sp. 
gr.,  0.960),  containing  10  per  cent.,  by  weight,  of  NH3;  and 
aqua  ammonias  fortior  (sp.  gr.,  0.901),  of  28-per-cent.  strength. 
Spiritus  ammonias  aromaticus  is  an  alcoholic  solution  contain- 
ing 10  per  cent.,  by  weight,  of  the  gas,  and  has  a  sp.  gr.  of 
0.810. 

Ca(HO)2  is  a  white  powder  slightly  soluble  in  H20,  form- 
ing liquor  calcis,  or  lime-water  (0.15  per  cent.).  It  is  less  sol- 
uble in  boiling  than  in  cold  water.  Glycerin  or  sugar  renders 
it  much  more  soluble:  8  grains  per  ounce.  Lime-water  is  used 
extensively  in  medicine  as  an  antacid  remedy,  and  is  an  effect- 
ive chemic  antidote  in  mineral-acid  poisoning.  Milk  of  lime  is 
an  aqueous  mixture  with  more  Ca(HO)2  than  will  dissolve  in 
the  water.  When  Ca(HO)2  is  exposed  to  the  air  it  changes  to 
the  carbonate  by  absorption  of  C02;  hence  the  setting  of  mor- 
tar into  plaster — also  due  partly  to  the  formation  of  a  silicate 
with  the  sand. 

Ba(HO)2  is  obtained  by  treating  BaO  with  H20.  It  is 
soluble  in  20  parts  of  H20,  forming  the  strongly  alkaline  test- 


INORGANIC  ACIDS.  153 

fluid  known  as  baryta-water,  which  is  clouded  by  the  least  trace 
of  C02.  Mg  (H0)2  is  very  slightly  soluble  in  H20,  with  which 
it  forms  a  gelatinous  mixture  ("milk  of  magnesia" — 1  to  15  of 
H20),  but  is  freely  soluble  in  solutions  of  NH4  salts.  Zn(HO)2 
is  a  white  ppt.  formed  by  the  addition  of  KHO  or  NaHO  to  a 
solution  of  a  zinc  salt.  It  dissolves  readily  in  excess  of  re- 
agent, forming  a  zincate. 

Au(HO)3,  auric  acid,  is  a  yellow-brown  ppt.  prepared  by 
heating  a  solution  of  AuCl3  with  magnesia  and  washing  ppt. 
with  dilute  HN03.  When  treated  with  excess  of  NH4HO  an 
explosive  brown  or  green  powrder,  known  as  fulminating  gold, 
is  produced.  Potassium  aurate,  KAu02.3H20,  appears  in  small, 
soluble,  yellow  needles  of  alkaline  reaction,  used  in  gilding  Cu. 

Cu(HO)2  is  a  light-blue,  bulky  ppt.,  partly  reduced  to 
black  CuO  on  boiling.  When  NH4HO  is  added  to  solutions  of 
cupric  salts  a  deep-blue  color  results,  owing  to  the  formation 
of  ammonio-copper  compounds  [CuS04(KE3)4  and  others]. 
A12(HO)6  is  an  insoluble  white  powder  much  used  as  a  mor- 
dant. 

Experiment. — Show  lake  formed  by  adding  Na2CO3  and  alum  solu- 
tions to  a  cochineal  solution.  The  acetate  is  commonly  employed,  the 
acetic  acid  being  driven  off  by  heat,  leaving  the  hydrate. 

In  the  presence  of  more  positive  oxids  A12(HO)6  may  act 
as  a  weak  base,  forming  aluminates. 

Lead  oxyhydroxid  [Pb(HO)2,PbO]  is  readily  soluble  in  ex- 
cess of  precipitating  caustic  alkali,  forming  plumbates  (K2Pb02, 
]S[a2Pb02),  which  on  boiling  throw  down  red  or  yellow  lead 
oxid.  Mn2(HO)6  is  a  dark-brown  substance  obtained  by  at- 
mospheric oxidation  of  white  Mn(HO)2,  and  is  used  in  var- 
nishes. 

Fe2(HO)6  is  a  reddish-brown  gelatinous  mass  or  magma, 
pptd.  from  ferric  chlorid  or  sulphate  by  the  addition  of  an 
alkaline  hydrate.  When  dissolved  in  ferric  chlorid  or  ferric 
acetate  solution  and  then  separated  from  the  crystalloid  sub- 
stances by  dialysis,  it  is  known  as  dialyzed  iron.  Both  this  and 
the  ordinary  freshly  prepared  hydrate  are  effective  chemic 
antidotes  for  As.  Fe2(HO)6  gradually  changes  to  oxyhydrate, 
Fe20(HO)4. 

Experiment. — By  means  of  NH4HO  ppt.  hydroxids  of  Bi,  Cd,  Cr, 
Co,  and  Ni,  and  note  color  of  each.  Which  are  soluble  in  excess  of 
reagent? 


THE  PROPERTY  OP 

HaboaiileiicalCillfipiftifiM! 

154  INORGANIC  CHEMISTRY. 


SALTS. 

HALOID  SALTS. 

General  Characters. — Mostly  white;  saline,  sharp,  or  bitter 
taste;  neutral  reaction;  cubic  crystals  mostly;  less  often  octa- 
hedra  or  rhombohedra;  freely  soluble  in  water  (except  Ag, 
Pb,  and  Hg1),  much  less  so  in  alcohol  (deliquescent  soluble); 
chiefly  binary  compounds;  ternary  salts  unstable. 

CHLORIDS. 

These  are  usually  formed  by  dissolving  a  metal  or  its 
hydrate  or  carbonate  in  HC1.  Next  to  water  NaCI  (common 
salt)  is  the  most  abundant  compound  in  Nature,  being  present 
in  all  natural  waters  and  soils  and  to  a  slight  degree  in  the 
atmosphere.  It  is  a  necessary  ingredient  of  the  fluids  of  ani- 
mals and  plants,  and  is  obtained  chiefly  from  the  salt-wells  of 
New  York  and  Michigan.  A  saturated  solution  contains  2.8 
parts  in  100  of  water.  A  normal  saline  solution  is  of  the  same 
percentage  as  the  blood, — namely:  0.6  per  cent., — and  is  used 
by  injection  into  the  rectum,  under  the  skin,  or  into  a  vein  as 
a  restorative  measure  in  cases  of  hemorrhage,  shock,  or  col- 
lapse. 

The  chief  sources  of  potassium  compounds  are  sylvite 
(KC1)  and  carnallite  (KCl,MgCl2.6H20),  mined  at  Stassfurt, 
Germany.  NH4C1  is  prepared  by  saturating  the  ammoniacal 
liquor  from  gas-works  with  HC1,  evaporating  to  dryness,  and 
subliming  the  residue  as  feathery  crystals.  It  is  used  exten- 
sively as  an  expectorant  and  in  calico-printing,  dyeing,  and 
soldering,  and  as  a  flux  in  refining  gold. 

Experiment. — To  10  c.c.  NH4OH  add  HC1  until  solution  is  neutral 
to  test-paper,  and  evaporate  to  dryness  on  water-bath.  What  is  the 
taste?  How  many  c.c.  of  the  acid  should  be  required  to  saturate? 

CaCl2  is  very  hygroscopic  (soluble  in  1.5  H20),  and  the 
fused  or  anhydrous  product  is  much  used  in  drying  gases  and 
in  the  quantitative  estimation  of  H  in  organic  bodies.  The 
hydrous  compound  CaCl2.6H20  when  mixed  with  powdered  ice 
or  snow  makes  an  effective  freezing-mixture.  Its  ready  sol- 
ubility renders  it  of  service  for  raising  the  b.p.  of  H20  in  the 
water-bath:  a  50-per-cent.  aqueous  solution  boils  at  112°. 

BaCl2  is  important  mainly  as  the  reagent  for  H2S04  and 
soluble  sulphates,  with  which  it  forms  the  very  insoluble  BaS04. 
MgCl2  is  found  in  sea-water  and  mineral  waters  and  carnallite 


HALOID  SALTS.  155 

beds,  and  is  a  frequent  impurity  in  table-salt.  It  is  used  in  the 
manufacture  of  artificial  stone  and  for  finishing  cotton  goods 
in  dye-works.  ZnCl2  is  soluble  in  three-tenths  of  its  own  weight 
of  water.  It  is  very  corrosive,  even  attacking  cellulose,  and  is 
used  as  a  caustic  and  in  weak  solutions  as  an  antiseptic,  astrin- 
gent, and  deodorant;  also  by  tinsmiths  (flux  for  solder)  and 
embalmers  and  to  preserve  wood.  The  official  liquor  contains 
50  per  cent,  of  the  salt. 

Hg2Cl2,  the  mild  chlorid,  or  calomel,  is  prepared  by  treat- 
ing any  mercurous  salt  with  HC1.  It  is  a  white,  odorless, 
tasteless,  and  impalpable  powder,  insoluble  in  all  ordinary 
solvents.  Calomel  volatilizes  without  first  melting,  and  is  the 
salt  used  for  mercurial  fumigation.  It  turns  black  on  the 
addition  of  any  hydrate,  being  changed  thus  to  the  correspond- 
ing oxid.  The  mild  chlorid  of  mercury,  in  the  presence  of  the 
free  HC1  of  the  gastric  juice,  is  apt  to  be  transformed  into  the 
poisonous  corrosive  chlorid.  This  change  can  be  prevented 
more  or  less  by  combining  with  the  calomel  NaHC03  to  neu- 
tralize the  acid  of  the  stomach.  The  spontaneous  decomposi- 
tion of  HgoCL  into  HgCl2,  that  sometimes  takes  place  on  ex- 
posure to  light  or  air,  can  be  detected  by  pouring  water  over 
the  powder  and  immersing  in  the  fluid  a  bright  strip  of  copper 
or  other  metal.  If  any  of  the  mercuric  salt  is  present  in  solu- 
tion, the  metal  will  soon  become  tarnished. 

HgCl2  (corrosive  sublimate)  is  obtained  by  treating  any 
other  mercuric  salt  with  HC1  or  a  chlorid.  It  appears  in  white 
crystals,  which  are  odorless,  but  have  a  sharp,  metallic  taste 
and  an  acid  reaction.  On  being  triturated  it  remains  pure 
white,  whereas  calomel  turns  of  a  yellowish  tinge.  HgCl2  is 
soluble  in  16  parts  of  cold  water,  2  of  boiling  water,  3  of  alco- 
hol, 4  of  ether,  and  14  of  glycerin.  The  aqueous  solution 
slowly  decomposes  in  the  light,  reacting  with  the  water  as  fol- 
lows:— 

2HgCl2  +  H20  =  Hg2Cl2  +  2HC1  +  0 

The  addition  of  a  weak  acid  or  of  NaCI  or  NH4C1  serves  to 
hinder  this  chemic  change;  these  other  chlorids  also  aid  the 
solubility  of  the  mercurial  salt  and  make  it  less  irritating.  The 
bichlorid  of  Hg  coagulates  albumin  (NH4C1  prevents),  and  is 
a  popular  antiseptic  in  the  strength  of  from  1-10,000  to  1-1000. 
It  should  never  be  used  to  sterilize  instruments,  as  it  rapidly 
corrodes  them,  the  metal  uniting  with  one  atom  of  Cl,  calomel 
being  deposited  on  the  surface.  The  "white  precipitate"  pro- 
duced by  treating  HgCl2  solution  with  NH4HO  is  used  in  oint- 
ments (official  strength,  10  per  cent.). 


156  INORGANIC  CHEMISTRY. 

Fe2Clg.l2H20  is  a  yellowish-red,  deliquescent  salt  prepared 
by  dissolving  the  oxid  in  HC1.  The  official  liquor  contains 
37.8  per  cent,  of  the  salt.  The  tincture  is  one-third  the 
strength  of  the  liquor,  being  diluted  with  3  volumes  of  alco- 
hol, which  reduces  ferric  chlorid  to  the  ferrous  state.  The 
corrosive  action  of  tincture  of  iron  on  the  teeth  is  due  to  the 
presence  of  free  HC1  in  this  preparation,  and  patients  should 
be  cautioned  to  rinse  out  the  mouth  after  taking  it  through  a 
glass  tube. 

Experiment. — Dissolve  with  heat  1  gm.  of  tine  iron  wire  in  4  c.c. 
of  HC1  and  2  c.c.  of  H,O.  Filter,  mix  with  one-third  as  much  HC1,  add 
slowly  and  gradually  10  m.  HN03,  and  evaporate  till  red  vapors  all 
escape.  Mix  with  4  c.c.  hot  water  and  set  aside  to  form  a  solid  mass 
of  Fe2Cl6.12H2O.  How  much  of  this  salt  and  how  much  FeCl2  can  be 
made  from  the  gram  of  iron? 

AuCl3.2H20  is  a  ruby-red  crystalline  compound  forming 
double  salts  with  HC1  and  Nadl.  AuCl3.NaCl  is  prepared  by 
rubbing  together  equal  parts  of  the  dry  salts.  It  appears  in 
orange-yellow,  deliquescent  prisms  used  in  medicine  and  den- 
tistry, in  gilding,  and  as  a  toning  agent  in  photography. 

PtCl4  appears  in  soluble,  reddish-yellow  needles,  obtained 
by  dissolving  Pt  in  aqua  regia  and  evaporating  the  HN03.  It 
is  used  as  a  reagent  for  the  quantitative  estimation  of  K,  NH4, 
and  alkaloids. 

A12C16  is  used  somewhat  in  weak  solutions  as  a  disin- 
fectant. SnCl2.2H20  occurs  as  white  needles.  It  is  employed 
as  a  mordant  in  dyeing  and  calico-printing,  and  is  also  a  strong 
reducing  agent,  precipitating  As,  Hg,  and  Au  as  metals  from 
solutions  of  their  salts.  SnCl4  is  a  colorless  liquid  forming 
crystals  with  one-third  as  much  -water,  and  much  used  as  a 
mordant  for  madder-red  colors.  A  solution  of  SbCL,  is  used 
extensively  for  giving  a  bronze  surface  to  iron  and  steel:  gun- 
barrels,  for  instance. 

Identification  of  Chlorids. — AgN03  in  presence  of  HN03  gives  a 
curdy,  white  ppt.,  insoluble  in  boiling  HN03,  but  instantly  soluble  in 
dilute  NH4HO  (1  to  20). 

CHLOEATES. 

KC103  and  NaC103  occur  as  colorless,  shining,  monoclinic 
prisms  with  a  cooling,  saline  taste.  On  heating  they  give  off 
0  with  deflagration.  Violent  explosions  may  result  when 
rubbed  with  S  or  dry  organic  substances.  Owing  to  their  oxid- 
izing action,  they  are  largely  employed  in  calico-printing  and 
the  manufacture  of  anilin  black.  The  K  salt,  soluble  in  16  1/2 
parts  of  H20,  is  used  as  a  detergent  healing  wash  in  disorders 


HALOID  SALTS.  157 

of  the  mouth  and  throat  and  in  the  manufacture  of  parlor- 
matches. 

Identification  of  Chlorates. — Same  reaction  as  chlorids  after  heat- 
ing solid  to  redness  and  dissolving  residue  in  water,  or  after  adding 
Zn  and  dilute  H2SO4  to  solution. 

HYPOCHLORITES. 

Ca(C10)2  is  met  with  chiefly  in  chlorinated  lime:  a  bleach- 
ing and  disinfecting  powder  which  contains  also  CaCl2  and  is 
prepared  by  passing  Cl  gas  over  slaked  lime.  NaCIO  occurs 
only  in  solution  as  liquor  sodae  chloratas,  which  should  contain 
2.6  per  cent,  of  available  CL  Its  disinfectant  action  depends 
both  on  the  Cl  and  the  nascent  0.  Hypochlorites  liberate  free 
Cl  rapidly  on  addition  of  acids,  and  slowly,  but  spontaneously, 
on  exposure  to  air,  heat,  and  light  through  a  reaction  with 
C02. 

Ca(C10)2.CaCl2  +  2C02  =  2CaC03  +  2C12 

Identification  of  Hypochlorites. — Odor  of  Cl.  Blue  color  with  KI, 
starch  paste,  and  acetic  acid. 

PERCHLORATES. 

When  KC103  is  heated  to  352°  it  is  decomposed  into 
KC104,  KC1,  and  0.  Further  heating  to  400°  breaks  up  the 
perchlorate  into  KC1  and  0.  KC104  is  of  no  practical  impor- 
tance. Like  chlorates,  it  must  be  reduced  to  the  chlorid  before 
striking  a  ppt.  with  AgN03. 

BROMIDS. 

These  salts  are  usually  made  from  Br  by  combining  it  with 
Fe  or  other  metal  and  then  decomposing  writh  a  carbonate  or 
hydrate.  They  have  a  pungent,  saline  taste,  are  very  soluble 
(except  Ag,  Pb,  and  Hg1)  in  both  water  and  alcohol,  and  exert 
generally  a  sedative  action  on  the  nervous  system.  On  heating 
they  fuse  and  volatilize,  with  liberation  of  Br.  They  are  also 
decomposed  by  sulphuric  and  nitric  acids.  The  official  salts  are 
KBr,  NaBr,  NH4Br,  LiBr,  CaBr2,  ZnBr2,  and  SrBr2.  AgBr  is 
used  largely  in  photography. 

Identification  of  Bromids. — AgNO3  gives  a  dirty-white  ppt.,  in- 
soluble in  HNO3,  slowly  soluble  in  NH4HO,  but  insoluble  in  dilute  (1  to 
20)  NH4HO. 

An  aqueous  solution,  well  shaken  in  a  long  tube  with  Cl  water 
and  a  few  drops  of  chloroform,  yields  a  yellow-brown  color,  soon  settling 
to  a  red  stratum. 


158  INORGANIC  CHEMISTRY. 

HYPOBROMITES. 

These  are  analogous  to  the  corresponding  chlorin  com- 
pounds. They  are  very  unstable,  and  hence  should  be  used 
fresh.  They  are  decomposed  by  heat,  leaving  a  bromid.  NaBrO 
is  a  useful  reducing  agent  in  the  estimation  of  urea  in  urine. 

BROMATES. 

These  insoluble  salts  are  of  analytic  interest  only.  KBr03 
accompanies  KBr  as  an  additional  product  of  KHO  and  Br2.  It 
is  reduced  to  bromid  by  heating  with  charcoal.  If  present  in 
a  bromid,  a  yellow  color  (Br)  is  produced  on  addition  to  the 
salt  of  dilute  H2S04. 

IODIDS. 

These  salts  are  made  directly  from  the  element,,  and  con- 
stitute our  most  valuable  alteratives.  Being  deliquescent,  they 
are  soluble  in  alcohol.  KI  is  dissolved  by  3/4  its  own  weight 
of  water,  18  of  alcohol,  or  2  1/2  glycerin.  Given  largely  diluted 
in  water,  it  is  a  standard  remedy  for  tertiary  syphilis  and  in  the 
treatment  of  chronic  metallic  poisoning.  It  appears  to  combine 
with  these  poisons  accumulated  in  the  tissues  so  as  to  render 
them  soluble,  and  thus  hasten  their  elimination. 

Nal  is  very  similar  to  the  K  salt,  but  milder  in  action. 

Because  of  its  volatile  alkali,  NH4I  is  of  special  service  in 
chronic  lung  troubles.  It  is  also  the  principal  constituent  of 
tincture  of  iodin  decolorized  with  ammonia.  The  salts  men- 
tioned appear  in  cubic  crystals,  but  SrI2.6H20,  also  official, 
occurs  in  hexagonal  plates,  and  ZnI2  in  octahedra.  The  pearly, 
micaceous  crystals  of  CdI2  are  used  by  photographers  in  iodized 
collodion.  Agl  is  a  heavy,  amorphous,  yellowish  powder,  sol- 
uble in  an  aqueous  solution  of  KCN"  or  KI,  and  has  consider- 
able use  in  photography. 

Hg2I2  is  a  bright-yellow,  insoluble  powder,  darkening  to 
green  on  exposure  to  light,  owing  to  decomposition  into  metal- 
lic Hg  and  HgI2.  HgI2  is  a  scarlet,  amorphous  powder  (some- 
times octahedral),  soluble  in  130  alcohol,  and  almost  insoluble 
in  water  unless  KI  is  also  present.  It  is  extensively  prescribed 
in  the  mixed  treatment  of  syphilis,  being  formed  here  by  reac- 
tion between  KI  and  HgCl2.  PbI2  is  a  very  slightly  soluble, 
heavy,  lemon-yellow  powder  used  in  ointments  and  plasters.  It 
is  distinguished  from  PbCr04  by  being  soluble  in  NH4C1  solu- 
tion on  boiling. 

There  are  three  iodids  of  As,  of  which  AsI3  is  official.  It 
appears  in  brilliant,  orange  scales,  soluble  in  7  parts  of  water 


NITRO-SALTS.  159 

or  30  of  alcohol.    Liquor  arseni  et  hydrargyri  iodidi  contains  1 
per  cent,  each  of  this  salt  and  HgI2. 

BiOI  has  been  utilized  to  some  extent  as  a  substitute  for 
iodoform.  FeI2  oxidizes  so  readily  on  exposure  to  air  (becoming 
insoluble)  as  to  require  protection  with  about  four  times  as 
much  sugar  of  milk  (ferri  iodidum  saccharatum).  Syrupus  ferri 
iodidi  contains  10  per  cent,  of  FeI2.  The  tasteless  syrup  is 
about  half  this  strength,  with  citric  acid,  forming  Fe2I6.  Each 
fluidram  of  syrupus  ferri  et  mangani  iodidi  has  6  grains  of  FeI2 
and  3  grains  of  MnI2. 

Identification  of  lodids. — AgNO-  gives  a  light-yellow  ppt.,  insol- 
uble in  both  HNO8  and  NH4HO. 

Starch  solution  and  a  few  drops  of  Cl  water  give  a  blue  color; 
destroyed  by  excess  of  Cl. 

IODATES. 

The  iodates,  like  the  chlorates,  are  unstable  compounds 
and  ready  oxidizers.  They  are  of  no  practical  interest.  KI03 
is  formed  along  with  KI  when  I2  is  added  to  KHO,  and  is 
reduced  to  iodid  by  heating  with  wood  charcoal.  To  detect 
KI03  present  as  an  impurity  in  KI  add  tartaric  acid  and  starch 
paste,  getting  a  blue  color.  The  periodate  may  be  prepared  by 
passing  Cl  into  a  mixture  of  KI  and  KHO. 

FLUORIDS. 

CaF2,  or  fluorspar,  is  a  common  rock,  used  extensively  as 
a  flux  in  metallurgic  operations.  Cryolite,  a  double  fluorid  of 
Al  and  Na,  is  of  importance  as  a  source  of  metal  Al,  as  is  also 
A12F6,  formed  by  passing  HF  over  heated  alumina.  Finely 
powdered  fluorids  warmed  gently  with  a  little  H2S04  liberate 
HF,  which  etches  glass,  as  described  under  the  latter  acid. 


NITRO-SALTS. 

General  Characters. — Unstable;  explosive;  ready  oxidizers; 
anhydrous;  white;  neutral  or  nearly  so;  cooling,  saline,  pun- 
gent taste;  soluble  in  water  (except  basic),  not  in  alcohol; 
deflagrate  on  heating;  refrigerants,  diuretics,  diaphoretics,  and 
vasodilators.  They  occur  in  Nature  commonly  as  an  efflores- 
cence on  walls  or  soils  wherever  organic  matter  is  undergoing 
decomposition  with  evolution  of  NH3,  which  oxidizes  under  the 
influence  of  nitrifying  ferments  into  HN02  and  HN03,  and 
these  unite  with  earthy  and  alkaline  mineral  matters.  Arti- 
ficially they  are  made  by  dissolving  a  metal  in  ETN"03.  On  heat- 
ing they  evolve  0  and  N02,  leaving  an  oxid  of  the  metal. 


160  INORGANIC  CHEMISTRY. 

NITRATES. 

KN"03  is  used  in  medicine,  fireworks,  the  refining  of  gold, 
and  as  a  meat-preservative  along  with  boric  acid,  borax,  and 
Na2C03.  Ordinary  gunpowder  is  3/4  KN03  and  about  1/8  each 
S  and  charcoal.  The  products  of  its  combustion  are  CO,  C02, 
S02,  N,  K2S,  etc.  NaN03  occurs  naturally 'as  an  abundant  de- 
posit in  the  dry  regions  of  South  America.  It  is  very  deliques- 
cent, and  is  used  chiefly  as  a  fertilizer;  also  as  a  meat  preserva- 
tive and  as  a  source  of  HN03  and  KN03.  NH4N03  is  utilized 
largely  in  the  production  of  the  mill  anesthetic  N20.  Ca(N03)2 
is  a  very  deliquescent  salt,  soluble  in  both  water  and  alcohol. 
Ba(N03)2  is  an  essential  ingredient  of  formulas  for  pale-green 
fires.  Sr(N03)2  is  used  in  pyrotechnics  because  of  the  brilliant- 
red  color  it  imparts  to  a  flame. 

AgN03  is  the  most  important  medicinal  salt  of  silver.  It 
appears  in  colorless,  transparent,  tabular,  rhombic  crystals,  sol- 
uble in  0.6  water  or  26  alcohol.  It  is  used  chiefly  for  its  cau- 
terant,  styptic,  or  astringent  effect  upon  diseased  mucous  mem- 
branes. In  contact  with  animal  matter  AgN03  breaks  up  into 
metallic  Ag,  which  stains,  and  free  HN03,  to  which  the  caustic 
properties  are  due.  It  is  used  further  in  hair-dyes,  indelible 
inks,  and  photography.  The  fused-nitrate  stick,  or  lunar  caus- 
tic, contains  a  little  AgCl  to  toughen  it.  The  mitigated  stick 
is  made  by  melting  together  1  part  of  AgN03  and  2  parts  of 
JxJN  U3. 

The  nitrates  of  Hg  are  prepared  by  dissolving  this  metal 
in  HN03,  the  product  being  mercurous  or  mercuric  according 
as  the  metal  or  the  acid  is  in  excess.  Hg2(N03)2.2H20  is  of 
interest  as  being  the  only  soluble  mercurous  salt;  but  in  the 
presence  of  much  water  an  insoluble  basic  compound  is  formed. 
Hg(N03)2  is  official  in  the  liquor  and  the  ointment. 

Pb(N03)2  appears  in  large  octahedra,  soluble  in  2  parts  of 
water.  It  is  used  in  the  manufacture  of  mordants  for  dyeing 
and  calico-printing.  Cu(N03)2.3H20  occurs  in  deep-blue,  deli- 
quescent crystals  that  are  highly  corrosive.  Bismuth  subnitrate 
(BiO)N03.H20,  is  a  heavy,  white,  tasteless,  insoluble  powder 
(mineral  acids  dissolve  it  readily).  Like  the  subcarbonate,  it 
is  used  for  its  local  sedative  effect;  also  as  a  cosmetic  and  in 
staining  glass  and  glazing  porcelain.  Ferrous  and  ferric  ni- 
trates are  used  in  dyeing.  Liquor  ferri  nitratis  is  a  6-per-cent. 
solution  of  Fe2(N03)6. 

Identification  of  Nitrates. — Mixed  with  a  solution  of  FeS04  in 
presence  of  H2SO4,  a  black  coloration  is  produced,  due  to  NO  absorbed 
by  ferrous  salt,  which  is  changed  to  ferric  sulphate  on  heating,  with 
disappearance  of  color. 


THIO-SALTS.  161 

One  drop  of  phenyl-sulplmric  acid  (1  part  of  carbolic  acid,  4  parts 
of  H,SO4,  2  parts  of  H2O)  added  to  salt  or  residue  evaporated  over 
water-bath  yields  a  reddish  color,  due  to  nitrophenol. 

NITRITES. 

KN02  and  NaN02  are  prepared  by  reducing  the  corre- 
sponding nitrates  by  heating  with  Pb  or  Cu.  They  are  light 
yellowish  in  color,  very  soluble  in  water,  and  mostly  soluble  in 
alcohol,  which  is  used  to  separate  nitrites  from  nitrates.  The 
Na  salt  is  the  essential  constituent  of  spirit  of  nitrous  ether, 
and  is  also  employed  in  the  manufacture  of  colors.  Pb,  Ag,  and 
4  nitrites  are  also  known. 


Identification  of  Nitrites.  —  Red  fumes  when  treated  with  strong 
H2S04. 

Dark-brown  color  with  FeSO4  without  previous  addition  of  H2S04. 

Instant  blue  color  with  KI  and  starch  paste  on  adding  a  few  drops 
of  HaSO*,  which  liberates  nitrous  acid. 

2HNO2  +  2HI  =  I2  +  2H20  +  2NO 


THIO-SALTS. 

General  Characters. — Usually  white,  and  acid  in  reaction 
(hydrosulphids  alkaline);  give  off  sulphurous  or  sulphureted 
odors  when  heated  or  treated  with  mineral  acids;  mostly  in- 
soluble, except  the  alkaline  salts  and  a  few  others.  Any  com- 
pound containing  S  responds  to  hepar  test,  which  is  to  fuse 
substance  on  charcoal  with  Na2C03  and  KCN  by  means  of  blow- 
pipe. The  sulphid  thus  formed,  when  placed  on  a  silver  coin 
and  moistened  with  dilute  HC1,  causes  a  black  stain  of  Ag2S. 

SULPHIDS. 

These  are  of  little  medical  interest,  though  of  extremely 
abundant  occurrence  in  Nature.  They  are  recognized  by  evolv- 
ing H2S  when  heated  with  HC1,  the  former  acid  being  readily 
detected  by  its  odor  and  characteristic  reactions.  A  delicate 
test  for  soluble  sulphids  is  the  transient  purple  color  produced 
by  sodium  nitroprussid.  Sulphids  insoluble  in  HC1  form  sul- 
phates on  heating  with  strong  HN03  or  nitrohydrochloric  acid. 
Polysulphids — K2S3,  for  instance — are  known  by  the  deep- 
yellow  or  orange  color  of  their  solutions,  and  by  evolving  H2S 
with  deposition  of  S  on  treating  with  HC1  or  dilute  H2S04. 

CS2  is  a  colorless,  volatile  liquid  (sp.  gr.,  1.268)  with  an 
ethereal  or  fetid  odor.  It  is  prepared  by  passing  vapors  of  S 
over  red-hot  coals.  It  is  soluble  in  alcohol,  ether,  chloroform, 


162  INORGANIC  CHEMISTRY. 

and  oils.  The  vapor  is  very  inflammable,  and  acts  as  a  depress- 
ant poison  when  inhaled.  CS2  is  a  powerful  solvent  of  rubber 
and  oils  (used  to  extract  seeds  and  animal  refuse),  S,  P,  and  I. 
and  an  efficient  insecticide.  On  account  of  its  great  refractive 
properties,  it  is  used  to  fill  the  hollow  glass  prisms  of  the  spec- 
troscope. 

Potassa  sulphurata  is  a  mixture  of  polysulphids  with  K2S04 
and  K2S203.  Calx  sulphurata  is  a  crude  CaS,  and  is  phosphor- 
escent in  the  dark.  HgS  occurs  as  a  black  variety  and  two  red 
ones,  used  in  paints,  namely:  cinnabar,  formed  by  sublimation 
of  black  HgS,  and  vermilion,  made  by  subliming  8  parts  S  with 
42  parts  Hg.  Vermilion  is  used  to  redden  the  rubbers  for 
artificial  dentures.  SnS2  is  a  gold-colored  scale  compound  used 
for  bronzing  wood  and  gypsum.  PbS  is  a  black  powder  used  for 
glazing  pottery.  As2S2  is  employed  as  a  red  coloring  agent  in 
leather  manufacture  and  in  the  preparation  of  white  or  Indian 
fire  (2  parts  with  7  S  and  24  KN03).  Amorphous  Sb2S3  is  used 
occasionally  as  an  emetic  and  more  frequently  in  vulcanizing 
caoutchouc,  giving  to  this  a  reddish-brown  color.  FeS,  obtained 
artificially  by  fusing  together  Fe  and  S,  serves  in  the  laboratory 
as  the  source  of  H2S.  FeS2,  the  native  pyrites,  is  of  immense 
importance  as  the  chief  source  of  H2S04  and  FeS04.  CdS  is  a 
yellow  pigment  used  by  artists.  Ag2S  (argentite,  or  vitreous 
silver)  is  found  in  Nature  in  dark-gray,  regular  crystals,  and 
the  so-called  oxidized  silver  is  ordinarily  prepared  by  coating 
with  a  thin  layer  of  Ag2S,  obtained  by  heating  together  Ag  and 
K2S.  NH4SH,  the  sulphydrate  or  hydrosulphid,  is  obtained  by 
saturating  water  of  ammonia  with  H2S  till  a  portion  of  the 
liquid  ceases  to  cause  a  white  ppt.  with  MgS04  solution.  It  is 
a  colorless  liquid,  becoming  yellow  on  exposure  to  the  air,  owing 
to  formation  of  higher  ammonium  polysulphids  and  free  S. 
The  neutral  compound  (NH4)2S  is  formed  by  adding  excess 
(two-thirds  more)  of  NH4HO.  Both  compounds  are  valuable 
reagents  in  analytic  group  work  of  the  heavy  metals.  Ca(SH)2 
is  known  only  in  solution  and  is  used  as  a  depilatory. 

SULPHATES. 

The  sulphates  are  bitter  salts  found  in  sea  and  salt-lake 
waters  and  many  minerals.  They  are  generally  soluble  in  water 
(except  Pb  and  alkaline  earths),  but  insoluble  in  alcohol.  They 
are  used  in  medicine  as  hydragog  cathartics  and  astringents. 

Na2S04.10H20  is  employed  in  glass  manufacture.  (NH4)2- 
S04,  prepared  by  saturating  ammoniacal-gas  liquor  with  H2S04, 
and  evaporating,  is  the  basis  for  the  manufacture  of  other  NH4 


THIO-SALTS.  163 

salts,  and  is  a  constituent  of  artificial  manure.  In  addition  to 
extensive  medical  employment,  MgS04  is  utilized  as  a  finisher 
in  dyeing  and  calico-printing. 

CaS04.2H20,  or  gypsum,  is  an  abundant  rock,  which,  when 
burnt  at  115°  so  as  to  lose  about  three-fourths  of  its  water  and 
then  ground,  is  known  as  plaster  of  Paris.  This  is  a  fine,  white 
powder  much  used  by  artists  (for  casts),  surgeons  (for  splints), 
and  dentists  (for  molds)  by  reason  of  its  "setting"  with  water, 
which  is  taken  up  as  water  of  crystallization,  forming  the  stone- 
like  gypsum  again.  Borax,  common  salt,  K2S04,  and  other 
compounds  quicken  this  process  by  facilitating  osmosis.  The 
K  salt  or  alum  and  gelatin  give  a  polished  surface  to  the  dry 
plaster.  Under  various  trade-names  plaster  of  Paris  is  used 
for  giving  a  hard  finish  to  plastered  walls.  Both  hydrated  and 
dehydrated  gypsum  are  soluble  in  dilute  acids  and  in  syrup. 
Gypsum  is  also  used  as  a  fertilizer  and  cement,  and  the  artificial 
salt  (pearl-hardening,  or  annaline)  is  employed  as  a  filling  for 
writing  paper. 

Experiment. — Prove  presence  of  water  of  crystallization  in  gypsum 
by  heating  a  lump  of  this  and  noticing  moisture  on  sides  of  tube  and 
loss  of  crystalline  appearance. 

BaS04  is  a  heavy,  very  insoluble  compound  used  to  give 
weight  to  cards  and  paper  and  as  a  pigment  in  water-colors, 
under  the  name  of  permanent  white,  since  it  does  not  blacken 
with  atmospheric  H2S. 

The  sulphates  of  the  heavy  metals  are  generally  astrin- 
gent, owing  to  the  S04  radical  being  combined  with  not  very 
positive  metals.  ZnS04  is  an  effective  irritant  emetic,  and  is 
used  in  finishing  cotton  goods.  CuS04.5H20  occurs  in  large 
deep-blue,  triclinic  crystals,  soluble  in  2.6  parts  of  water,  used 
as  an  astringent,  as  a  mordant,  in  electrotyping,  and  in  gravity 
batteries.  CuS04,4NH3.H20,  made  by  adding  excess  of  NH4HO 
to  solution  of  CuS04,  is  used  as  a  styptic  and  as  a  test  for  As. 
The  yellow  subsulphate  of  mercury,  Hg(HO)2S04,  is  a  nearly 
insoluble  powder  sometimes  employed  as  an  emetic. 

The  alums  are  double  sulphates  comprising  an  alkaline  and 
a  sesquisulphate  (Fe,  Mn,  Cr,  Al)  and  24  molecules  of  water 
of  crystallization.  Common,  or  potash,  alum  [K2A12(S04)4.24- 
H20]  forms  large,  colorless,  efflorescent  octahedra  having  .a 
sweetish  and  strongly  astringent  taste  and  soluble  in  10  1/2 
parts  of  water.  It  is  much  used  as  a  mordant  in  dyeing,  calico- 
printing,  and  in  the  form  of  "lakes"  for  pigments. 

Experiment. — Show  insoluble  lake  formed  by  adding  Na2CO3  and 
saturated-alum  solution  to  a  cochineal  solution",  and  note  how  the 


1G4  INORGANIC  CHEMISTRY. 

supernatant  liquid  is  decolorized.    The  acetate  is  usually  employed,  the 
acetic  acid  being  driven  off  by  heat,  leaving  the  hydrate. 

Alum  loses  all  its  water  of  crystallization  (45  per  cent.)  on 
heating  to  200°,  leaving  dried,  or  burnt,  alum,  which  is  much 
less  soluble  than  the  hydrous  salt,  and  is  mildly  escharotic  be- 
cause of  its  avidity  for  water.  Ammonia  alum  [A12(NH4)2- 
(S04)4.24H20]  has  the  same  appearance  and  properties  as  potash 
alum  and  is  somewhat  more  soluble.  Al  may  be  replaced  by 
other  metals,  forming  ferric  alum  [Fe2(NH4)2(S04)4.24H20], 
manganese  alum,  or  chrome  alum.  Soda  alum  is  much  used 
as  the  acid  element  in  cheap  baking-powders.  This  practice  is 
reprehensible,  since  a  part  of  the  salt  changes  in  the  stomach 
into  phosphate  and  hydrate  of  Al,  both  of  which  are  soluble  in 
the  gastric  juice,  and  the  continued  use  of  such  baking-powders 
leads  to  chronic  dyspepsia  and  nervous  disorders.  Hot  alum 
solutions  make  a  good  "pickle"  for  dissolving  borax  glass  from 
metals  after  soldering. 

MnS04.4H20  appears  in  rose-colored  crystals,  soluble  in 
an  equal  weight  of  water.  It  produces  a  permanent  brown  dye. 
FeS04.7H20  occurs  as  large,  light-green,  efflorescent  crystals, 
soluble  in  water,  but  not  in  alcohol.  It  is  found  in  Nature  in 
ferruginous  mineral  waters.  It  is  used  for  making  ink  and  as 
a  disinfectant.  It  destroys  organic  matters  by  abstracting 
their  0.  Fe2(S04)3  is  a  white  mass  dissolving  in  H20  to  make  a 
reddish-brown  solution  of  liquor  ferri  tersulphatis.  This  is 
styptic  and  hemostatic,  like  the  subsulphate:  Fe40(S04)5. 

Identification  of  Sulphates. — BaCl2  produces  a  white  ppt.  of  BaS04, 
insoluble  in  boiling  water  (if  reagent  crystallizes  out,  this  dissolves)  and 
also  in  boiling  HNO3.  Insoluble  sulphates  (Ba,  Sr,  Ca,  and  Pb)  must 
first  be  boiled  with  KHO  or  NaHO,  or  be  ignited  with  an  alkaline  car- 
bonate and  the  blow-pipe  on  a  piece  of  clean  charcoal. 


SULPHITES. 

These  are  usually  prepared  by  passing  gas  from  burning  S 
into  solution  of  a  hydrate,  forming  acid  or  normal  salts,  accord- 
ing to  the  relative  amount  of  the  reagents.  They  are  unstable 
salts,  gradually  changing  to  sulphates  on  exposure  to  the  air; 
act  as  reducing  agents;  and  are  decomposed  by  heat  (some  into 
oxids  and  S02,  others  into  sulphids  and  sulphates).  The  alka- 
line sulphates  are  soluble;  all  others  insoluble.  They  are  of 
very  little  use  in  medicine,  though  the  sulphite  of  K  and  the 
sulphite  and  bisulphite  of  Na  are  official.  NaHS03  is  used  in 
solid  form  and  in  solution  as  a  preservative  and  a  bleaching 
agent.  This,  like  all  sulphites,  evolves  S02  without  deposition 


CARBON  SALTS.  165 

of  S  on  heating  with  acids.  CaS03  is  used  as  a  preservative  by 
cider-makers,  and  the  same  salt  in  excess  of  H2S03  is  employed 
by  brewers.  Benzoinated  Na2S03  has  been  utilized  by  dentists 
as  a  deodorant. 

Identification  of  Sulphites. — BaCl2,  added  to  a  neutral  solution, 
gives  white  ppt.  of  BaSO3,  soluble  in  dilute  HC1. 

AgijSOg  darkens  on  boiling,  owing  to  decomposition  into  H2S04  and 
metallic  Ag. 

THIOSULPHATES. 

Na2S203.5H20,  the  commercial  "hyposulphite,"  is  soluble 
in  two-thirds  of  its  own  weight  of  water,  but  insoluble  in  alco- 
hol. It  is  used  extensively  in  photography,  under  the  name  of 
"hypo,"  to  dissolve  the  unaltered  halogen  compounds  of  Ag. 
It  is  also  employed  to  remove  the  excess  of  Cl  in  bleaching  and 
paper-manufacture  and  in  lixiviating  silver-ores. 

Identification  of  Thiosulphates.— Dilute  or  strong  HC1  or  H.,SO4 
drives  off  SO,  and  produces  a  yellow  deposit  of  S. 

HYPOSULPHITES. 

NaHS02,  the  true  hyposulphite,  is  used  in  dyeing  and  to 
reduce  indigo  and  in  the  estimation  of  free  0  in  the  laboratory. 
The  hyposulphite  of  Ag  and  Na  is  very  soluble,  and  does  not 
coagulate  albumins  nor  stain  the  skin. 


CARBON  SALTS. 

General  Characters,  —  Carbonates  and  bicarbonates  are 
usually  white  and  generally  alkaline,  because  of  the  weak  acid 
radical.  Carbonates  are  generally  insoluble,  except  alkaline; 
bicarbonates  of  alkalies  and  alkaline  earths  are  soluble.  Bicar- 
bonates are  formed  by  passing  excess  of  C02  into  carbonate 
solution.  Carbonates  are  generally  prepared  by  passing  CO, 
into  solution  of  hydrate  or  by  double  decomposition  of  a  soluble 
carbonate  and  soluble  salt  of  the  base.  Both  give  off  C02  on 
treating  with  acids,  which  dissolve  them;  the  bicarbonates  also 
on  simple  heating  above  50°.  Bicarbonates  tend  to  break  down 
spontaneously  into  C02,  H20,  and  carbonates,  which,  being  less 
soluble,  form  sediments  and  deposits. 

CARBONATES   AND   BICARBONATES. 

K2C03  is  derived  from  wood-ashes,  fermented  beet-roots, 
molasses,  sheep's  wool,  carnallite,  and  kainite.  It  is  soluble  in 
a  little  more  than  its  own  weight  of  water,  but  insoluble  in 


166 


INORGANIC  CHEMISTRY. 


alcohol.    Na2C08.10H20  is  found 

in  the  ashes  of  all  plants,  espe- 
cially  those   growing   near   salt- 
water  and   in   the    Caspian   and 
other  seas.    It  is  commonly  man- 
ufactured in  Europe  from  NaCl 
and  H2S04  by  the  Leblanc  proc- 
ess, the  resulting  sulphate  or  salt 
cake   being  reduced   to    sulphid 
with   C  in  a  revolving  furnace, 
and  at  the  same  time  caused  to 
react  with  limestone.    This  crude 
soda,   or   black   ash,   is   used   in 
bleaching,  soap-making,  and  the 
g       manufacture  of  green  glass.    Pu- 
3       rification  is  effected  by  lixiviation, 
I       evaporating  the  concentrated  so- 
3       lution,  and  crystallization.     The 
ammonia-soda  process  is  preferred 
s       in  the  United  States.    It  consists 
^      in   running    common    salt    solu- 
tion through  NH3  gas  and  then 
|       through  a  saturated  solution  of 
§       C02.      The    resulting    sparingly 

1  soluble  NaHC03  is  converted  into 
a      normal  carbonate  by  heat.    Na2- 

2  C03  is  soluble  in  16  H20  or  1 
part  glycerin,  but  is  insoluble  in 
alcohol.     It  is   of  great  impor- 
tance  as   the   base   from   which 
many  other  sodium  salts  are  pre- 
pared.    NaHC03  is  employed  in 
textile  industries  for  its  alkaline 
effect  in  scouring  wool  and  un- 
gumming  silk.     It  is  a   compo- 
nent of  most  baking-powders,  be- 
ing combined  in  these  with  starch 
and  some  compound  with  an  acid 
reaction,  preferably  KHC4H406. 
In  presence  of  heat  and  moisture 
the  two  opposing  salts  react  to 

liberate  C02,  which  raises  the  dough  and  renders  the  baked 
loaf  light  and  porous. 

NaHC03  +  KHC4H406  =  KNaC4H406  +  C02  +  H20 


i!i!i 


CARBON  SALTS.  167 

The  official  ammonium  carbonate  is  a  compound  acid  am- 
monium carbonate  with  ammonium  carbamate,  and  has  the 
formula  NH4HC03.NH4NH2C02.  It  appears  in  hard,  striated 
masses,  with  ammoniacal  odor  and  sharp,  saline  taste.  When 
exposed  to  air  it  loses  both  NH3  and  C02.  A  solution  of  the 
normal  salt  for  reagent  purposes  is  obtained  by  adding  NH4HO 
(prevents  absorption  of  C02  and  formation  of  bicarbonate). 
Aromatic  spirit  of  ammonia  is  a  solution  of  normal  carbonate 
in  diluted  alcohol,  flavored  with  essential  oils. 

Li2C03  requires  80  parts  of  water  to  dissolve  it.  It  is  used 
medicinally  as  a  uric  acid  solvent.  CaC03  is  prescribed  as  an 
antacid,  chiefly  in  the  form  of  native  chalk  prepared  by  elutria- 
tion.  Precipitated  chalk  is  formed  by  the  reaction  between 
Na2C03  and  CaCl2.  It  is  non-crystalline,  and  is  used  in  tooth- 
powders.  Whiting  and  Paris  white  are  impure  forms  of  chalk 
used  for  polishing  agents.  Common  putty  is  a  mixture  of  whit- 
ing and  linseed-oil.  BaC03  and  SrC03  are  used  as  bases  for 
the  preparation  of  other  salts. 

Magnesia  alba  [(MgC03)4Mg(OH)2.5H20]  is  an  official 
compound  prepared  by  boiling  each  in  80  parts  of  water,  10 
parts  MgS04,  and  12  Na2C03;  the  solutions,  mixed  in  the  cold, 
are  then  boiled  for  fifteen  minutes  and  strained.  It  is  a  loose, 
white,  bulky  mass,  odorless,  and  of  an  earthy  taste;  practically 
insoluble  in  H20,  but  dissolved  readily  by  dilute  acids,  with 
active  effervescence,  giving  off  761  volumes  of  C02.  It  is  also 
quite  soluble  in  NH4C1  solutions.  It  is  used  as  an  antacid,  and 
is  cathartic  in  the  presence  of  acids.  The  heavy  carbonate  of 
the  British  Pharmacopeia  is  prepared  by  mixing  the  above 
reagents  each  in  20  times  as  much  H20  and  evaporating  to 
dryness. 

The  official  zinc  carbonate  is  an  amorphous,  impalpable, 
pale  pink-brown  powder  of  inconstant  composition,  which  is 
usually  expressed  as  2ZnC03.3Zn(OH)2.  Almost  totally  insol- 
uble in  water  and  alcohol,  it  dissolves  readily  in  dilute  acids, 
carbonated  waters,  and  ammonium  hydrate  and  carbonate. 
Ag2C03  differs  from  other  carbonates  in  being  yellow  and 
turning  black  on  exposure  to  air  and  light.  Malachite  and 
azurite,  the  native  basic  carbonates  of  Cu,  are  green  and  blue, 
respectively,  and  are  used  for  ornamental  purposes.  Hg2C03 
and  basic  mercuric  carbonates  are  unimportant  light-yellow  and 
brownish-red  salts. 

White  lead,  or  basic  lead  carbonate  [(PbC03)2Pb(OH)2], 
manufactured  from  lead  by  exposing  it  to  the  simultaneous 
action  of  air,  C02,  and  vapors  of  acetic  acid,  is  of  immense 
industrial  importance  as  the  basis  of  most  paints,  for  which 


168  INORGANIC  CHEMISTRY. 

purpose  it  is  ground  with  7  per  cent,  linseed-oil  or  turpentine 
and  often  variously  colored.  The  basic  bismuth  carbonate 
[(BiO)2C03.H20]  is  a  white  powder  used  in  medicine  for  its 
antacid  and  local  sedative  effect,  being  quite  insoluble  in  water. 
Official  FeC03  is  protected  from  atmospheric  oxidation  by  ad- 
mixture with  sugar. 

Identification  of  Carbonates  and  Bicarbonates. — They  effervesce 
with  any  acid,  except  H2S  and  HCN,  giving  off  a  colorless,  odorless  gas 
which  turns  lime-water  milky.  Soluble  carbonates  give  a  white  ppt. 
with  cold  solutions  of  MgSO4;  bicarbonates  not.  HgCl2  gives  a  reddish- 
brown  ppt.  with  carbonates  of  K,  Na,  and  Li;  a  white  ppt.  with  their 
bicarbonates. 

CARBIDS. 

The  only  carbid  of  interest  is  CaC2,  lustrous,  dark-brown, 
hard,  brittle  masses,  prepared  by  heating  in  an  electric  furnace 
a  mixture 'of  lime  and  coal  or  coal-tar.  It  is  important  as  being 
the  source  of  acetylene-gas. 

STTLPHOCARBONATES. 

These  salts  resemble  carbonates  in  constitution,  but  con- 
tain S  in  place  of  0. 


PHOSPHO-SALTS. 

General  Characters. — Usually  white;  efflorescent;  cooling, 
saline  taste.  Alkaline  phosphates,  phosphites,  and  pyrophos- 
phates  soluble  in  water,  but  not  alcohol;  others  soluble  in 
dilute  acids.  Hypo-salts  all  soluble,  unstable  when  in  solution 
— usually  protected  by  sugar.  They  act  chiefly  as  laxatives  and 
mild  biliary  stimulants,  except  hypo-salts,  which  are  used  as  a 
medium  for  the  administration  of  P. 

PHOSPHATES,   OR   ORTHOPHOSPHATES. 

These  are  prepared  by  neutralizing  (or  a  little  more)  H3P04 
with  a  hydrate  or  carbonate.  Three  classes  of  salts  are  formed 
according  as  1,  2,  or  3  H  atoms  of  the  tribasic  acid  are  replaced 
by  the  metal;  2  atoms  are  always  replaced  when  the  acid  is 
neutralized  by  a  carbonate.  Trisodic  phosphate,  Na3P04.12H20, 
is  alkaline  in  reaction.  On  exposure  to  air  it  absorbs  C02,  form- 
ing Na2C03  and  disodic  phosphate.  This  latter,  Na2HP04.- 
12H20,  is  the  official  and  commercial  phosphate  of  sodium,  and 
is  the  salt  on  which  the  alkalinity  of  the  blood  depends  largely. 
It  appears  in  large,  monoclinic  prisms,  soluble  in  5.8  H20,  but 


PHOSPHO-SALTS.  169 

insoluble  in  alcohol.     At  a  red  heat  it  changes  to  the  pyro- 
phosphate: — 

2Na2HP04  =  Na4P207  +  H20 

Monosodic  phosphate,  NaH2P04.H20,  has  an  acid  reaction, 
and  is  the  chief  source  of  urinary  acidity.  Microcosmic  salt, 
NaNH4HP04.4H20,  on  heating  gives  off  water  and  NH3  and 
forms  a  clear  glass  (sodium  hexametaphosphate)  on  cooling. 
Hence  it  is  used  in  blow-pipe  analysis.  Li3P04  is  noteworthy 
as  being  the  only  insoluble  Li  salt. 

Ca3(P04)2  occurs  for  the  most  part  in  the  southern  United 
States  and  West  Indies  in  the  phosphate  rock  made  up  largely 
of  the  bones  of  prehistoric  marine  animals.  It  is  extracted  with 
HC1  and  precipitated  with  NH4HO.  It  dissolves  readily  in  solu- 
tions of  ammonium  salts,  NaN03,  NaCl,  etc.  It  is  prescribed 
in  the  syrup  of  calcium  lactophosphate  and  is  also  used  very 
extensively  as  a  fertilizer.  Acid  phosphate  or  "superphosphate 
of  lime"  is  a  mixture  of  CaS04  and  CaH4(P04)2,  prepared  by 
treating  bones  or  phosphate  rock  with  two-thirds  as  much,  by 
weight,  of  H2S04.  It  is  employed  in  cheap  baking-powders  and 
as  a  fertilizer,  being  a  necessary  ingredient  of  seeds. 

Normal  magnesium  phosphate,  Mg3(P04)2,  is  also  found 
in  bones.  AgaP04  is  a  pale-yellow,  amorphous  compound. 
Mn2(P04)2.2H20  is  a  greenish-gray  powder.  Ferri  phosphas 
solubilis  is  an  official  scale  preparation  containing  Fe2(P04)2. 
Fe3(P04)2  is  a  slate-colored  compound  turning  blue  in  the  air. 
It  has  been  found  in  phthisic  sputa,  in  pus,  and  in  disinterred 
bones. 

Identification  of  Phosphates. — BaCL  gives  white  ppt.,  soluble  in 
acetic  and  all  stronger  acids. 

Solution  of  (NH4),MoO4  in  HN03  yields  a  yellow  ppt.,  insoluble  in 
HN03,  but  soluble  in  NH4HO. 

AgN03  gives  lemon-yellow  ppt.,  soluble  both  in  HNO3  and  NH4HO. 


PYROPHOSPHATES. 

As  the  name  indicates,  these  salts  are  prepared  by  heat- 
ing orthophosphates  to  250°.  There  are  two  series,  according 
as  2  or  4  H  atoms  of  the  acid  are  replaced.  Na4P207.10H20 
is  official,  and  occurs  in  colorless,  transparent,  monoclinic 
prisms  or  a  crystalline  powder.  Fe4(P207)3  is  the  salt  present 
in  the  official  scale  preparation  ferri  pyrophosphas  solubilis. 

Identification  of  Pyrophosphates. — AgN03  gives  white  ppt.  in  neu- 
tral solutions,  soluble  both  in  HX03  and  in  NH4HO. 


170  INORGANIC  CHEMISTRY. 

METAPHOSPHATES. 

These  salts  are  prepared  by  heating  the  ortho-salts  to  red- 
ness. By  polymerization  five  series  of  salts  are  formed,  viz.: 
RP03,  metaphosphate;  R2P206,  dimetaphosphate;  R3P309, 
K4P4012;  and  K6P6018,  hexametaphosphate.  They  are  of  no 
practical  interest.  They  give  the  same  reaction  as  that  above 
under  pyrophosphates,  and,  in  addition,  coagulate  albumin. 

PHOSPHITES. 

They  are  strong  reducing  agents,  and  burn  on  Pt  foil.  The 
general  formula  of  these  salts  is  R2HP03.  They  are  of  no 
consequence.  They  are  distinguished  from  hypophosphites  by 
yielding  ppts.  with  Ba  'and  Ca  hydrates  and  with  Pb(C2H302)2. 

HYPOPHOSPHITES. 

These  salts  are  prepared  from  the  Ca  or  Ba  salt  by  double 
decomposition  with  a  carbonate.  The  hypophosphites  are  active 
reducing  agents,  and  should  not  be  rubbed  with  oxidizing  agents 
for  fear  of  an  explosion.  When  heated  in  a  dry  test-tube  they 
give  off  H3P,  which  ignites  spontaneously  with  a  yellow,  phos- 
phorescent flame. 

Experiment. — Boil  together  in  solution  any  hypophosphite  and 
HgCl2,  and  note  ppt.,  first,  of  white  calomel  and  then  black  mercury. 
KH2PO2  is  soluble  in  0.6  water  and  in  7.3  alcohol;  NaPH2O2.H2O  in  1 
water  or  30  alcohol;  Ca(H2P02)2  in  6.8  water,  not  in  alcohol; 
Fe2(PH202)8  sparingly  in  water,  not  at  all  in  alcohol.  The  official  syrup 
contains  the  first  three  salts  just  mentioned. 

Identification  of  Hypophosphites. —  (NH4)2MoO4  gives  a  fine,  blue 
ppt. 

PHOSPHIDS. 

The  only  phosphid  of  any  importance  is  Zn3P2.  It  is  made 
by  direct  union  of  P  and  melted  Zn,  and  appears  as  a  gritty, 
dark-gray  powder  or  minutely-crystalline,  friable  fragments 
with  metallic  luster.  It  is  insoluble  in  water  or  alcohol,  but 
dissolves  in  HC1,  with  evolution  of  H3P.  It  is  a  convenient 
medium  for  administration  of  P. 

BORATES. 

Orthoborates,  from  H3B03,  are  very  unstable.  The  meta- 
borates,  from  HB02,  are  more  stable,  but  of  no  practical  con- 
sequence. The  pyroborates  are  very  stable.  The  most  impor- 


ARSENITES  AND  ARSENATES.  171 

tant  pyroborate  is  borax,  Na2B407.10H20,  which  is  obtained  as 
a  sediment  from  the  borax  lakes  of  Persia,  Thibet,  California 
(Death  Lake),  and  Nevada  (Pyramid  Lake).  It  is  a  white,  pris- 
matic, crystalline,  feebly  alkaline  substance,  soluble  in  16  parts 
of  water  and  less  than  2  of  glycerin;  it  is  insoluble  in  alcohol. 
On  heating  sufficiently  borax  swells  up  and  loses  its  water  of 
crystallization,  fusing  into  a  glass-like  body.  Borax  beads  pre- 
pared in  this  way  have  a  great  affinity  for  oxids,  and  with  the 
blow-pipe  give  characteristic  colors  in  the  oxidizing  and  reduc- 
ing flames  for  certain  metals.  This  avidity  of  borax  for  oxids 
explains  its  use  as  a  cleansing  agent  in  the  processes  of  welding, 
brazing,  and  soldering,  and  as  a  flux  in  refining.  It  is  also 
employed  as  a  preservative  and  in  the  manufacture  of  certain 
kinds  of  glass,  soap,  and  enamels.  Glycerin  or  mineral  acids 
liberate  H3B03  from  borax. 

Na2B407.10H20  +  2C3H5(HO)3  =  2C3H5B0 

+  3H20  +  10H20 
C3H5B03  +  3H20  =  H3B03  +  C3H5(HO)3 

Identification  of  Borates.  —  CaCl2,  rendered  slightly  alkaline  with 

H3 


,  on  heating  gives  white  ppt.,  soluble  in  HC2H3O2. 
On  rendering  solution  just  acid  with  HC1,  turmeric  paper  dipped 
in  it  turns  brownish  red  on  drying,  changing  to  green  on  moistening 
with  KHO. 

ARSENITES   AND   ARSENATES. 

These  are  very  poisonous  salts.  All  but  the  alkaline  are 
insoluble.  The  most  important  is  K3As03,  of  which  liquor 
potassii  arsenitis  is  a  1-per-cent.  alkaline  solution  flavored  with 
compound  tincture  of  lavender.  Sodium  arsenite  and  arsenate 
are  used  for  cleansing  in  calico-printing.  Scheele's  green, 
CuHAs03,  is  a  common  green  pigment.  Paris  green,  well  known 
as  a  pigment  and  insecticide,  has  the  formula  Cu(C2H302)2,- 
3Cu(As03)2. 

Of  the  arsenates,  Na2HAs04.7H20  is  used  in  medicine, 
liquor  sodii  arsenatis  being  a  1-per-cent.  solution.  It  is  soluble 
in  4  parts  water  and  very  sparingly  in  alcohol.  On  fusing  ar- 
senic with  alkaline  carbonates  pyro-arsenates,  analogous  to 
pyrophosphates,  are  formed. 

Identification  of  Arsenites.  —  Yellow  ppt.  with  AgN03  or  with  H2S 
in  presence  of  HC1;  green  ppt.  with  CuSO4.  Usual  tests  for  As. 

Identification  of  Arsenates.  —  React  same  as  phosphates,  except 
that  arsenates  give  a  brick-red  ppt.,  instead  of  yellow,  with  AgNO3. 
Insoluble  arsenates  should  be  boiled  with  NaHO,  filtered,  and  the  nitrate 
exactly  neutralized  with  dilute  HN03  before  testing  with  AgN08. 


172  INORGANIC  CHEMISTRY. 

ANTIMONATES. 

The  acid  pyro-antimonate  of  Na  (Na2H2Sb207.6H20)  is 
noteworthy  as  being  the  only  insoluble  compound  of  this  metal. 
Potassium  metantimonate  (2KSb03.5H20)  is  a  gummy  or 
crystalline  mass  prepared  by  deflagrating  Sb  and  KN03,  boil- 
ing with  water,  and  allowing  to  evaporate. 

Identification  of  Antimonates. — Strong  HC1  throws  down  white 
ppt.  of  HSb03.  (See  also  tests  for  Sb.) 

CHROMATES. 

These  salts  are  all  characterized  by  being  colored  yellow, 
red,  or  orange.  Chromates  of  the  alkalies  are  soluble;  other 
chromates  generally  insoluble.  They  are  irritant  poisons. 

K2Cr04  occurs  in  yellow,  rhombic,  weakly  alkaline  crystals, 
soluble  in  2  parts  water.  On  adding  acids  its  solutions  turn  red, 
owing  to  the  formation  of  the  dichromate,  K2Cr207.  This  salt 
is  soluble  in  10  water,  the  solution  being  acid.  It  is  an  oxidiz- 
ing agent  (with  H2S04)  used  extensively  in  dyeing  and  tanning 
and  in  photography.  It  is  the  source  of  the  other  Or  com- 
pounds. 

!N"a2O04  and  Na2O207  are  similar  to  the  K  salts,  but  are 
more  soluble.  PbCr04  is  much  used  in  paints  under  the 
name  of  chrome-yellow.  Chrome-red  is  a  basic  lead  chromate, 
PbCr04,Pb(HO)2.  BaCr04  is  also  employed  as  a  pigment  under 
the  name  of  yellow  ultramarine.  The  soluble  chromates  pre- 
cipitate Ba,  but  not  Ca,  from  solutions. 

Identification  of  Chromates. — Pb(C2H302)2  or  BaCl2  give  a  yellow 
ppt.,  soluble  in  HNO3,  but  not  in  HC2H3O2;  KHO  darkens  (green)  and 
dissolves  the  lead  salt. 

Treated  with  excess  of  H2SO4  and  shaken  up  with  ozonized  ether, 
a  brilliant-blue  color  appears. 

Acids  turn  chromate  solutions  orange;  alkalies  turn  dichromates 
yellow. 

MANGANATES. 

These  are  unstable  oxidizing  compounds,  only  the  alkali 
salts  dissolving  in  H20,  forming  green  solutions.  K2Mn04  so- 
lution on  standing  (quickly  on  boiling)  changes  to  perman- 
ganate, its  color  at  the  same  time  passing  from  dark  green 
through  blue  and  violet  to  red. 

3K2Mn04  +  2H20  =K2Mn208  +  4KHO  +  Mn02 

Experiment. — Heat  strongly  in  a  casserole  equal  parts  of  MnO2, 
KHO,  and  KC1O3.  Let  cool  and  then  dissolve  out  green  K2MnO4  with 
water.  Pour  this  solution  into  more  water,  and  note  that  it  becomes 
violet  (K2Mna08),  with  ppt.  of  Mn,(HO)6. 


SILICATES.  173 

K2Mn208  appears  in  dark-purple,  metallic,  lustrous  prisms, 
soluble  in  16  H20.  It  is  a  powerful  oxidizing  agent,  deodorant, 
antiseptic,  and  disinfectant:  in  neutral  solutions  giving  off  3 
atoms  of  0;  in  acid  solutions  5  atoms.  A  common  method  of 
sterilizing  the  hands  is  to  wash  them  first  in  K2Mn208  solution 
and  then  remove  this  stain  with  oxalic  acid,  followed  by  alco- 
hol. The  other  permanganates  are  similar  to  the  K  compound. 
Asbestos-paper  should  be  used  in  filtering  solutions  of  man- 
ganates  or  permanganates. 

Experiment. — Add  a  few  drops  of  absolute  alcohol  to  powdered 
K:,Mn.,08.  Ignition  takes  place. 

identification  of  Manganates. — Dilute  acids  change  to  perman- 
ganates with  the  gamut  of  colors  above  mentioned. 

Identification  of  Permanganates. — Purple-red  solutions,  entirely 
decolorized  by  H2C2O4.  Evolves  Cl  on  mixing  with  HC1. 

STANNATES. 

Stannic  and  metastannic  acids  dissolve  in  alkalies  to  form 
salts  known  as  stannates  and  metastannates.  The  most  impor- 
tant compound  is  sodium  stannate,  or  "preparing  salts,"  Na2- 
Sn03.4H20,  used  largely  as  a  mordant  in  dyeing  and  calico- 
printing.  The  alkaline  metastannates,  K2H8Sn5015,  are  also 
used  in  dyeing. 

Identification  of  Stannates. — HC1  ppts.  white  gelatinous  H2SN03. 
(See  tests  for  tin.) 

ZINCATES   AND   ALUMINATES. 

These  soluble  salts  are  formed  when  Zn  or  Al  is  dissolved 
in  an  alkaline  hydrate.  Their  respective  radicals  are  (Zn00)n 
and  (Al204)n. 

TTTNGSTATES. 

Sodium  tungstate,  ]STa2W04,  is  used  in  making  fire-proof 
fabrics. 

SILICATES. 

Although  forming  the  great  mass  of  the  earth's  crust,  the 
silicates  are  not  much  employed  in  medicine.  Felspars  are 
fusible  silicates  of  Al  and  K  or  Na.  These  rocks  break  down 
into  clays,  ordinarily  colored  with  Fe  (ocher),  mixed  with  CaC03 
(marl)  or  organic  detritus  (loam).  Kaolin,  or  china  clay,  is  the 
purest  native  Al  silicate,  and  has  the  approximate  composition 
Al4(Si04)3.4H20.  Topaz  is  fluoro-aluminum  silicate;  turquoise, 
A14(P04)2(HO)6.2H20.  The  precious  green  stone  beryl  is  a 
silicate  of  Al  and  Be. 


174  INORGANIC  CHEMISTRY. 

The  best-known  artificial  silicate  is  Na2Si03,  or  soluble 
glass,  liquor  sodii  silicatis,  which  is  prepared  by  fusing  sand 
with  excess  of  Na2C03  and  running  the  melted  mass  into  water. 
It  is  used  for  surgical  bandages.  K2Si03  is  also  soluble.  Fuller's 
earth  is  a  smooth  earth  useful  as  a  skin  dressing  for  infants. 

Glass  is  a  silicate  of  various  metals.  Bohemian,  or  hard, 
glass  is  made  by  heating  together  in  proper  proportions  lime, 
sand,  and  K2C03.  It  is  difficult  to  fuse,  and  resists  the  cor- 
rosive action  of  chemicals;  hence  is  used  extensively  for  labora- 
tory utensils.  Crown,  or  soft  window-,  glass  is  a  Na  and  Ca 
silicate,  with  addition  of  a  little  Fe  and  Al.  Bottle  glass  con- 
tains more  Fe  and  Ca  and  less  K.  Flint,  or  crystal,  glass  is  a 
silicate  of  K  and  Pb;  it  is  readily  fusible,  lustrous,  and  highly 
refractive  to  light,  on  which  account  it  is  chosen  for  making 
lenses  and  other  optic  apparatus.  The  color  of  colored  glass 
depends  on  a  small  quantity  of  some  metallic  oxid:  Co  gives 
blue;  Mn,  amethyst;  ferrous,  bottle-green;  ferric,  brownish 
yellow  or  black;  Cr,  greenish  yellow;  cuprous,  ruby;  cupric, 
bluish  green.  Oxids  of  Zn  and  Sn  and  Ca2(P04)2  give  a  white 
opacity  to  glass. 

Porcelain  is  made  from  a  paste  of  water  and  kaolin,  to 
which  some  silica  (silex)  is  added  to  prevent  cracking  on  dry- 
ing, and  also  felspar  to  act  as  a  flux  and  vitrifying  cement.  The 
unglazed  fired  or  kiln-burnt  product  is  then  dipped  into  a  thin 
cream  of  the  glaze  (same  as  body,  with  excess  of  felspar  to 
render  very  fusible),  dried,  and  burned  again  at  a  white  heat. 
The  porcelain  is  colored,  if  desired,  with  metallic  oxids,  cobalt- 
blue,  chrome-green,  etc. 

Dental  porcelain  for  artificial  teeth  contains  a  relatively 
large  percentage  of  felspar,  so  as  to  render  them  more  trans- 
lucent and  life-like.  The  different  enamel  shades  are  secured 
by  the  use  of  purple  of  Cassius,  spongy  Pt,  oxid  of  Ti  (rutile- 
yellow),  or  gold  and  CoO  (blue  points);  for  dental  uses  the  silex 
and  felspar  are  heated  to  white  heat,  plunged  into  cold  water, 
and  ground  fine.  Kaolin  is  purified  by  twice  washing,  letting 
settle,  and  decanting,  then  drying  in  the  sun. 

The  dry  method  of  preparing  enamel  has  three  steps:  1. 
Preparing  metallic  oxid  by  fusing  tin,  silver,  and  gold  with 
borax;  removing  borax  glass;  dissolving  the  silver  in  H]ST03; 
washing  and  drying  residue.  2.  Fritting,  or  uniting  this  powder 
by  heat  with  a  flux  of  quartz,  borax  glass,  and  Na2C03.  3. 
Diluting  frit  with  sufficient  felspar  to  secure  desired  shade. 

Stoneware  is  a  coarse  porcelain  made  from  clays  contain- 
ing Fe203  and  a  little  CaO  to  render  somewhat  fusible.  Glazing 
may  be  accomplished  simply  by  throwing  into  the  furnace  NaCl, 


SILICATES. 


175 


which  forms  a  fusible  silicate  of  Na  over  the  surface  of  the 
vessels.  The  finest  earthenware  is  prepared  from  white  clay 
mixed  with  considerable  Si02  by  drying,  tiring,  and  dipping  into 
a  readily  fusible  glaze  mixture,  which  often  contains  PbO;  then 
drying  and  refiring.  Colored  designs  are  printed  on  paper  with 
oil  and  enamel  pigment  and  then  transferred  to  the  ware  before 
glazing.  The  oxids  of  Pb  and  Sn  yield  a  whitish,  opaque  glaze, 
which  may  be  attacked  by  acids  and  lead  to  poisoning. 

Kaolin  contains  about  40  per  cent.  A1203  and  46  per  cent. 


Fig.  28. — Interior  of  Pottery  Kiln. 

Si02;  the  fusible  clays  used  for  common  earthenware  are  two- 
thirds  Si02  and  one-fourth  A1203;  fire  clays  contain  a  large 
proportion  of  Si02;  brick-maker's  clay  is  about  one-half  Si02 
and  one-third  A1203.  Clays  are  "acid"  or  "basic"  according  to 
the  relative  amount  of  Si02  and  A1203.  The  change  caused  by 
heating,  from  plastic  to  hard  and  porous,  is  due  to  expulsion 
of  the  combined  H20. 

Cements,  or  hydraulic  mortars,  are  basic  silicates  of  lime 
and  alumina  made  by  burning  calcareous  clays  or  cement-rock 
or  suitable  artificial  mixtures.  They 


176  INORGANIC  CHEMISTRY. 

plaster  of  Paris:  by  taking  up  water  into  combination.  Com- 
mon, or  Koman,  cements  are  derived  from  clay  or  rock  burnt 
below  the  sintering-point.  Portland  cement  is  such  a  mixture 
of  limestone  and  clay  or  rock  as  will  yield,  on  burning  till 
sintered,  a  product  containing  55  to  60  per  cent,  of  CaO,  22 
to  25  per  cent,  of  Si02,  and  7  per  cent,  of  A1203. 

Ultramarine  is  a  blue  coloring  matter  consisting  of  sili- 
cates of  Na  and  Al  with  Na2S.  It  is  made  by  heating  to  red- 
ness in  fire-clay  crucibles  a  mixture  of  kaolin,  charcoal,  and 
sodium  sulphate  or  carbonate.  The  resulting  green  mass  is 
roasted  with  S  till  the  required  shade  of  blue  is  obtained.  The 
color  is  destroyed  by  heating  with  HC1,  H2S  being  evolved. 
When  dry  gaseous  HC1  and  air  are  passed  over  common  ultra- 
marine at  100°-150°,  its  color  is  changed  to  red  or  violet. 

Asbestos,  or  amianth,  is  a  fibrous  silicate  of  Ca  and  Mg. 
It  is  infusible  and  a  poor  conductor  of  heat.  It  is  used  for 
household  utensils,  as  a  fireproof  lining  material  in  buildings, 
and  as  a  non-conducting  packing  for  steam-apparatus  and 
boilers. 

Identification  of  Silicates.— On  adding  HC1  or  NH4C1  to  a  soluble 
silicate,  nearly  transparent  gelatinous  H4SiO4  is  precipitated.  On  drying 
and  heating  to  150°  and  dissolving  away  chlorids  with  dilute  HC1,  Si02 
is  left  as  a  gritty,  white  powder.  Insoluble  silicates  are  first  rendered 
soluble  by  fusing  with  5  parts  of  mixed  K  and  Na  carbonates. 

A  bead  of  microcosmic  salt  (NaNH4HPO4)  touched  with  the  pow- 
dered silica  or  silicate  becomes  opaque  and  shows  within  a  floating  mass 
called  the  "silica  skeleton." 


ORGANIC  ACID  SALTS. 

General  Characters.  —  Generally  soluble,  except  oxalates; 
many  have  characteristic  odors,  especially  on  heating  or  treat- 
ing with  mineral  acids;  char  when  heated  on  Pt  (except  for- 
mates; oxalates  turn  a  little  gray)  and  leave  residue  of 
carbonate  or  oxid;  changed  mostly  to  carbonates  in  blood, 
rendering  this  more  alkaline  and  urine  less  acid. 

OXALATES. 

These  salts  have  an  intensely  sour  taste.  The  alkaline 
oxalates  are  the  only  soluble  ones  (BaC204  slightly  soluble), 
the  NH4  salt  being  used  as  a  reagent  for  Ca  solutions.  Ce2- 
(C004)39H20  is  a  white,  granular,  tasteless  powder,  insoluble 
except  in  mineral  acids.  At  red  heat  it  leaves  a  yellow  or 
salmon  mixture  of  oxids.  CaC204  is  often  found  in  urinary  sedi- 
ments and  may  give  rise  to  concretions.  K2Fe(C204)2  is  a 


ORGANIC  ACID  SALTS.  177 

strong  reducer,  and  is  used  as  a  developing  solution  in  photog- 
raphy. KHC204,  like  the  acid,  is  very  poisonous.  It  is  used 
somewhat  to  bleach  straw  and  remove  ink-stains. 

Identification  of  Oxalates. — Cad,  in  neutral  or  alkaline  solution 
gives  white  ppt.  of  CaC2O4,  insoluble  in  acetic,  but  soluble  in  hydro- 
chloric, acid. 

Dry  insoluble  oxalates  heated  in  a  test-tube  evolve  inflammable 
CO  and  leave  a  carbonate  (effervesces  with  acids). 

ACETATES. 

These  are  made  by  neutralizing  carbonates  or  hydrates 
with  HC2H302.  Neutral  acetates  are  all  soluble  freely  in  water 
and  less  so  in  alcohol;  basic  acetates  are  insoluble  unless  a 
little  HC2H302  is  added  to  form  a  neutral  acetate.  Official  are 
the  acetates  of  K,  Na,  Zn,  and  Pb;  also  in  the  liquors  of  NH4, 
Fe  and  NH4  (red),  and  lead  subacetate,  Pb(C2H302)2.PbO.  This 
last  is  an  effective  sedative  astringent.  The  others  have  gen- 
erally a  diuretic,  refrigerant,  and  alkaline  action.  Lead-water, 
liquor  plumbi  subacetatis  dil.,  is  a  soothing  lotion  made  with  4 
dr.  liquor  plumbi  subac.  in  a  pint  of  distilled  water.  Both  these 
absorb  C02  on  exposure  and  become  milky.  A12(C2H302)6  and 
Fe2(C2H302)4  are  used  as  mordants  in  dyeing  under  the  names 
"red  liquor"  and  "iron  liquor."  The  former  is  also  employed 
by  dentists  as  a  disinfectant  and  deodorant.  The  basic  acetate 
and  aceto-arsenite  of  Cu  are  common  green  pigments. 

Identification  of  Acetates. — Odor  of  HC2H3O2  when  heated  with 
H,SO4;  apple-like  odor  of  acetic  ether  on  adding  alcohol. 

Deep-red  color  [Fe,(C2H3O2)6]  with  neutral  Fe2Cl6;  color  discharged 
both  by  HC1  and  HgCl2. 

VALERIANATES. 

These  yield  the  characteristic  odor  of  valerian  when 
warmed  or  moistened.  The  official  salts  are  those  of  NH4,  Fe, 
and  Zn.  They  are  soluble  in  water  and  in  alcohol. 

Identification  of  Valerianates. — Odor  of  valerian  on  heating  with 
H2SO4;  distillate  with  Cu(C2H302)2  solution  forms,  in  time,  oily  ppt., 
which  gradually  solidifies  into  greenish-blue,  crystalline  solid. 

TARTRATES. 

These  are  important  medicinal  salts.  Soluble  tartrates 
prevent  precipitation  of  ferric  and  other  hydroxids  by  alkalies, 
forming  soluble  salts.  KHC4H406  appears  in  somewhat  gritty, 
white,  rhombic  crystals,  with  acid  reaction  and  pleasant  taste. 
It  is  sparingly  soluble  in  water  and  insoluble  in  alcohol.  Be- 

12 


178  INORGANIC  CHEMISTRY. 

cause  of  this  fact,  it  is  thrown  out  of  solution  as  a  creamy  de- 
posit (cream  of  tartar)  of  argols  during  alcoholic  fermentation 
in  wine-casks.  It  is  used  largely  as  the  acid  ingredient  of  good 
baking-powders.  K2C4H406  is  a  very  soluble,  saline  purgative. 
KNaC4H406.4H20  forms  large,  colorless,  slightly  bitter,  rhom- 
bic prisms,  with  a  cooling,  saline  taste.  It  dissolves  in  1.4  H20, 
and  is  a  useful  mild  hydragog. 

Tartar  emetic,  2KSbOC4H406.H20,  is  a  white,  crystalline 
substance,  with  sweetish,  disagreeable  taste,  quite  soluble  in 
water,  and  slightly  in  alcohol.  It  is  a  depressing  emetic,  and 
is  used  as  a  mordant  in  dyeing.  Compound  syrup  of  squills 
contains  3/4  grain  of  this  salt  to  the  ounce,  and  a  solution  in 
alcohol  and  white  wine  forms  official  vinum  antimonii.  Tar- 
trate  of  Fe  and  NH4  and  of  Fe  and  K  are  non-constipating,) 
soluble,  garnet-red  scale  compounds,  formed  by  dissolving 
Fe2(OH)6  in  the  acid  tartrate  of  NH4  or  K.  Seidlitz,  or  com- 
pound effervescing,  powder  consists  of  120  grains  of  Eochelle 
salt  (KNaC4H406.4H20)  with  40  grains  NaHC03  wrapped  in 
the  blue  paper,  and  35  grains  H2C4H406  wrapped  in  white 
paper. 

Identification  of  Tartrates. — Neutral  solutions  (free  from  more 
than  a  trace  of  NH4  salts)  give  with  CaCL  a  white  ppt.,  which  after 
washing  dissolves  readily  in  cold  KHO,  and  is  again  pptd.  on  boiling. 

Ca(HO)2  in  excess  causes  ppt.  in  the  cold,  soluble  in  NH4C1. 

AgNO3  gives  white  ppt.,  turning  black  on  boiling. 

Char  rapidly  on  heating  to  dull  redness,  and  give  distinct  odor  of 
burnt  sugar. 

CITRATES. 

These  salts  are  prepared  by  dissolving  hydroxids  or  car- 
bonates in  H3C6H507.  All  have  a  cooling  taste  and  are  soluble 
except  BiC6H507  (soluble  in  NH4HO).  White,  crystalline  salts 
include  K3C6H507.H20,  Li3C6H507,  and  BiC8HB07.  The  cit- 
rates of  Fe,  Fe  and  NH4,  Fe  and  quinin,  Fe  and  strychnin,  and 
of  Bi  and  KE4  are  scale  preparations.  Mg3(C6H507)2  is  official 
as  an  effervescent  salt  and  in  the  liquor  magnesii  citratis.  This 
last  is  made  by  dissolving  Mg  carbonate  in  a  slight  excess  of 
citric-acid  solution,  adding  syrup  of  lemon,  placing  the  diluted 
liquid  in  a  strong,  round  bottle;  dropping  in  crystals  of  KHC03; 
then  corking,  wiring,  and  shaking  till  crystals  are  dissolved.  It 
is  a  mild  and  pleasant  laxative.  Elixirs  of  Bi  contain  Bi  and 
NH4  citrate.. 

Identification  of  Citrates. — No  ppt.  in  the  cold  with  CaCl,  and 
slight  excess  of  NH4OH,  but  on  boiling  white  Ca:!(CfiH5OT)2  is  thrown 
down.  When  ppt.  filtered  hot  and  washed  with  a  little  boiling  water, 


ORGANIC  ACID  SALTS.  179 

it  is  quite  insoluble  in  cold  KHO,  but  readily  soluble  in  neutral  solution 
of  CuCl2  or  NH4C12. 

Ca(HO)2  in  excess  does  not  cause  ppt.  till  mixture  is  boiled. 

AgNO3  produces  white  ppt.,  but  no  metallic  mirror  on  boiling. 

Dry  citrates  char  slowly  on  heating,  giving  slight  odor  of  burnt 
sugar. 

LACTATES. 

All  are  soluble  to  some  extent  in  water  and  insoluble  in 
ether.  The  official  metallic  lactatcs  are  Fe(C3H503)2.3H20  and 
Sr(C3H503)2.3H20.  The  former  appears  in  sweetish,  light- 
green  needles  or  crusts,  and  is  slowly  soluble  in  H20;  the  latter 
is  a  white,  slightly  bitter,  granular  or  crystalline  powder,  sol- 
uble both  in  water  and  in  alcohol. 

Identification  of  Lactates. — AgNO3  when  boiled  gives  a  dark  ppt., 
which  leaves  a  blue  liquid  on  subsiding. 

Strong  solutions  of  alkaline  lactate  boiled  with  HgN03  ppts.  pink 
or  crimson  HgC3H5O3. 

TANNATES  AND   GALLATES. 

The  salts  of  tannic  acid  are  bitter,  amorphous,  and  gen- 
erally insoluble.  They  are  the  essential  ingredients  in  nearly 
all  vegetable  bitters  and  astringents  (exceptions  are  columbo, 
gentian,  quassia,  and  chiretta).  Ferrous  tannate  is  the  basis  of 
most  black  writing-ink.  The  basic  gallate  of  Bi  (dermatol)  is 
a  yellow,  insoluble  powder  used  in  skin  diseases. 

Identification. — Fe2Cl6  in  neutral  solutions  gives  a  blue-black  ppt. 
decolorized  by  H2C2O4. 

OLEATES. 

KC18H3302  and  NaC18H3302  are  the  only  oleates  soluble 
in  water.  Acid  oleates  are  all  liquid,  and  soluble  in  oils,  fats, 
ether,  and  cold  absolute  alcohol.  The  oleates  of  Hg11  and  other 
heavy  metals  (usual  strength  2  per  cent.)  are  used  in  ointments 
where  penetrating  power  is  desired.  They  are  made  by  dissolv- 
ing the  oxid  in  oleic  acid.  They  do  not  stain  linen  or  become 
rancid,  and  seem  to  exert  considerable  antiseptic  action.  Oleates 
of  aconitin,  veratrin,  morphin  (5  per  cent.),  quinin  (25  per 
cent.),  and  other  alkaloids  are  formed  by  simple  solution  in 
oleic  acid.  Pb(C18H3302)2,  or  lead  or  diachylon  plaster,  is  made 
by  boiling  for  several  hours  PbO  with  twice  its  weight  of  olive- 
oil  and  one-third  as  much  water.  It  is  a  white,  viscid  mass, 
soluble  in  ether,  and  is  the  basis  of  the  thirteen  official  plasters. 

Identification  of  Oleates. — They  do  not  separate  from  ether  or 
alcohol  when  a  hot  solution  is  cooled.  Pb (C^H^C^h  is  pptd.  by 
Pb(C2H302)2,  and  is  almost  entirely  soluble  in  ether. 


180  INORGANIC  CHEMISTRY. 

STEARATES. 

Alkaline  stearates  are  alone  soluble  in  water.  KC18H3502 
is  soft  soap;  NaC18H3502,  hard  soap. 

Identification  of  Stearates. — HC1  and  heat  separate  free  stearic 
acid,  which  floats  as  an  oily  liquid,  and  solidifies  to  a  white  mass  on 
cooling.  Pb(C18H3B02)2  is  insoluble  in  ether. 


FORMATES. 

These  are  all  easily  soluble  in  H20  [except  Pb(CH02)2  and 
Hg(CHO)2],  and  are  strong  reducing  agents.  They  are  of  no 
medical  interest. 

Identification  of  Formates. — They  decompose,  without  charring, 
at  a  red  heat. 

Heated  with  H2SO4  they  evolve  CO,  which  burns  with  a  pale-blue 
flame. 

SUCCINATES. 

These  unimportant  salts  are  neutral  (E2C4H404)  or  acid 
(BHC4H404).  Alkaline  succinates  are  soluble;  others  diffi- 
cultly or  not  at  all.  Succinates  are  distinguished  by  giving  a 
bulky,  brownish-red  ppt.  with  neutral  Fe2Cl6;  also  with  BaCl2 
no  ppt.  at  first,  but  a  white  one  on  addition  of  ammonia  and 
alcohol  (distinction  from  benzoates). 


MALATES. 

K2C4H405  occurs  with  the  free  acid  in  apples,  currants, 
and  other  fruits.  The  malates  are  freely  soluble.  They  are 
recognized  by  adding  CaCl2,  which  gives  no  reaction  until  boil- 
ing or  addition  of  alcohol,  when  a  white  ppt.  is  thrown  down. 

BENZOATES. 

These  are  colorless,  crystalline,  soluble  salts  with  a  slight 
odor  of  benzoin.  They  are  chiefly  used  as  urinary  antiseptics, 
being  particularly  indicated  when  this  fluid  is  ammoniacal, 
since  the  benzoates  are  eliminated  by  this  route  as  hippuric 
acid.  Used  in  medicine  are  the  benzoates  of  KE4,  Li,  Na,  Bi, 
and  Hg.  They  are  prepared  by  neutralizing  benzoic  acid  with 
the  desired  hydrate  or  carbonate. 

Identification  of  Benzoates. — Fe2Cl6  in  solution,  rendered  slightly 
alkaline  with  NH4HO,  gives  flesh-colored  or  light-red  ppt.,  soluble  in 
benzoic  and  other  acids. 


ORGANIC  ACID  SALTS.  181 

SALICYLATES. 

These  are  important,  white,  mostly  solid,  deliquescent, 
medicinal  compounds  with  sweetish,  alkaline,  nauseating  taste, 
made  by  dissolving  alkaline  hydroxids  in  salicylic  acid.  Their 
specific  curative  effect  in  rheumatism  is  due  in  part  to  their 
alkaline  constitution  raising  the  alkalinity  of  the  blood,  and  in 
part  probably  to  a  destructive  action  on  the  unknown  rheumatic 
germs.  The  best-known  salts  are  NaC7H503,  soluble  in  1.5 
water  and  in  6  alcohol;  and  LiC7H503,  also  very  soluble.  The 
disagreeable  taste  can  be  disguised  to  some  degree  by  giving 
the  salt  in  some  aromatic  water:  cinnamon  or  peppermint,  for 
example.  Bi(C7H503)3  is  a  white,  odorless,  tasteless,  insoluble 
powder,  used  as  an  internal  and  intestinal  antiseptic  and  astrin- 
gent. 

Identification  of  Salicylates. — Fe2Cl6  gives  a  reddish-violet  color, 
even  in  very  dilute  solutions. 

Methyl-salicylate,  formed  by  warming  a  salicylate  with  alcohol  and 
one-fourth  the  volume  of  H2S04,  is  recognized  by  the  odor  of  winter- 
green. 

CARBOLATES,   OR   PHENATES. 

Carbolic  acid  unites  with  bases  to  form  soluble  antiseptic 
carbolates,  which  are  capable  of  dissolving  large  quantities  of 
phenol.  NaC6H50  appears  in  fusible,  pinkish  needles,  and  is 
used  in  dentistry  as  an  astringent,  styptic,  and  disinfectant. 
Phenol-mercury  [Hg(C6H50)2]  is  a  yellow,  crystalline  substance 
made  by  the  reaction  between  an  alcoholic  solution  of  NaC6H50 
and  of  HgCl2. 

Identification  of  Carbolates. — Fe2Cl6  causes  a  reddish-violet  color. 
Odor  of  carbolic  acid  is  evolved  on  heating  alone  or  with  H2SO4. 

SULPHOCARBOLATES. 

When  carbolic  acid  is  dissolved  in  H2S04,  sulphocarbolic 
acid,  C6H4OHS03H,  is  formed,  and  this  on  dilution  and  mixture 
with  oxids,  hydrates,  or  carbonates  yields  colorless  soluble  sul- 
phocarbolates.  NaC6H5S04.2H20  and  Zn(C6H5S04)2.H20  are 
both  valuable  intestinal  antiseptics,  the  latter  salt  being  also 
astringent. 

Identification  of  Sulphocarbolates. — Similar  reactions  as  carbo- 
lates, but  also  give  reaction  of  sulphates  with  BaCl2  after  fusing  with 
KN03  and  redissolving  residue  in  dilute  HC1. 

MECONATES. 

The  opium  alkaloids  occur,  for  the  most  part,  as  meconates 
(R2C7H207.3H20).  Normal  alkaline  salts  are  soluble  in  water; 


182  INORGANIC  CHEMISTRY. 

the  acid  salts  very  slightly.  Meconates  of  the  heavy  metals 
are  soluble  in  HC2H302.  Meconates  are  readily  recognized  by 
striking  with  Fe2Cl6  a  red  color,  not  cleared  up  by  HgCl2  or 
dilute  HC1. 

CYANO-SALTS. 

General  Characteristics. — Generally  poisonous,  mostly  col- 
orless, prismatic;  odor  of  HCN  or  bitter  almonds  on  wetting 
or  heating  with  acids;  sharp,  slightly  bitter,  alkaline  taste; 
alkaline  and  alkaline  earthy  salts  and  Hg(CN)2  soluble  in  H20, 
and  sparingly  or  not  at  all  in  alcohol  (except  cyanates).  The 
soluble  cyanids  dissolve  insoluble  ones,  forming  double  salts. 

CYANIDS. 

KCN  is  a  deliquescent  compound,  soluble  in  2  H20,  used 
for  reduction  of  metallic  oxids,  and  especially  as  a  solvent  of 
Ag  salts  in  photography  and  of  Au  and  Ag  in  electroplating 
and  in  the  extraction  of  Au  from  its  ores.  AgCN  and  Hg(CN)2 
are  white  powders,  turning  dark  on  exposure  to  light.  The 
isocyanids,  isonitrils,  or  carbylamins  are  non-toxic  liquid  hy- 
drocarbon derivatives  with  an  extremely  offensive  odor. 

Identification  of  Cyanids. — AgNO3  in  excess  gives  a  curdy,  white 
ppt.,  soluble  in  NH4HO  and  in  strong  boiling,  but  not  dilute,  HN03; 
ppt.  turns  brown  on  exposure  to  light. 

Insoluble  cyanids  yield  (CN)2,  smelling  like  peach-kernels,  when 
heated  in  dry  test-tube;  draw  out  open  end  into  jet  and  light  gas,  which 
shows  a  purple-red  flame. 

CYANATES,   OR   ISOCYANATES. 

KCNO  appears  in  white  scales,  and  is  employed  in  the 
preparation  of  organic  compounds.  NH4CNO  is  a  white,  crys- 
talline mass,  which  changes  to  its  isomer  urea  on  heating. 

Identification  of  Cyanates. — On  moistening  they  yield  the  corre- 
sponding bicarbonate. 

SULPHOCYANIDS,    SULPHOCYANATES,    OR   THIOCYANATES. 

KCNS,  NaCNS,  and  KH4CNS  give  a  blood-red  color  with 
ferric  compounds,  and  are  used  to  distinguish  ferric  from  fer- 
rous salts.  Hg(CNS)2  is  a  white,  insoluble  powder,  which  swells 
up  greatly  on  decomposing  by  heating,  and  is  used  in  the  cone- 
shaped  toys  called  "Pharaoh's  serpents." 

Identification.— On  heating  with  H,S04,  HCN  is  evolved,  with 
characteristic  odor,  and  S  is  deposited.  Also  the  ferric  test  mentioned 
above. 


QUESTIONS.  .  183 

FERROCYANIDS. 

K4Fe(CN)6.3H20  is  manufactured  on  a  large  scale  by 
fusing  horns,  hoofs,  leather,  etc.,  with  potash  and  adding  iron. 
It  appears  in  yellow  crystals,  used  in  dyeing  and  in  making 
KCN,  HCN,  and  the  pigment  Prussian  blue,  Fe4(FeCy6)3. 

Identification  of  Ferrocyanids. — Any  ferrous  salt  gives  a  white 
ppt.,  quickly  changing  blue;  any  ferric  salt  a  dark-blue  ppt.  of  Prussian 
blue,  insoluble  in  HC1,  turned  reddish  brown  by  KHO,  the  blue  color 
being  restored  by  adding  HC1. 

Pb,  Zn,  Ag,  and  Hg  solutions  give  white  ppts.;  cupric  salts  a 
reddish-brown  ppt.,  insoluble  in  acids,  but  soluble  in  NH4HO. 

FERRICYANIDS. 

These  salts  are  produced  by  oxidation  of  solutions  of  the 
ferrocyanids  with  01.  The  0  is  given  off  in  the  presence  of  free 
alkali,  red  prussiate  of  potash  [K6Fe2(ClSr)12],  changing  back 
to  yellow  prussiate,  or  ferrocyanid. 

Identification  of  Ferricyanids. — Any  ferrous  salt  ppts.  dark  Turn- 
bull's  blue  [Fe:,Fe2(CN)i2],  insoluble  in  acids,  decomposing  with  boiling 
KHO  into  K6Fe2Cy12  and  dirty  green  Fe(HO)2. 

Any  ferric  salt  gives  a  brownish  coloration,  and  throws  down 
Turnbull's  or  Prussian  blue  on  adding  reducing  agents  (H2S03  or  SnCl2). 
Lead  and  mercuric  salts  give  no  ppt.;  stannous  salts,  white  ppt.;  mer- 
curous  solutions,  brownish  red;  AgNO3,  orange. 

NITROPRTJSSIDS. 

These  salts  are  formed  by  the  action  of  HN03  on  ferro- 
cyanids, NO  replacing  a  CTN".  The  only  one  of  practical  in- 
terest is  sodium  nitroprussid  [Na2Fe(CN)5NO.H20],  which 
appears  in  red  prisms  and  is  used  as  a  reagent. 


QUESTIONS   ON  INORGANIC   CHEMISTRY. 

Metals. 

1.  Name  the  alkali  metals  and  the  metals  of  the  alkaline  earths. 

2.  Which  is  more  potent,  KBr  or  NaBr,  and  why? 

3.  If  a  cubic  inch  of  Fe  and  a  cubic  inch  of  Sn  were  both  heated 
to  the  same  temperature  and  placed  on  a  cake  of  paraffin,  which  would 
melt  the  wax  first? 

4.  What  metals  decompose  H20,  and  why? 

5.  Write  equation  for  decomposition  of  H.,0  with  red-hot  Fe. 

6.  W7hat  two  metals  rank  first  as  conductors  of  heat  and  elec- 
tricity ? 

7.  Wrhy  do  silver  spoons  tarnish? 

8.  How  can  one  separate  Hg  from  other  metals? 

9.  At  what  temperature  does  Hg  distil? 


184  INORGANIC  CHEMISTRY. 

10.  What  objection  to  sterilizing  Al  instruments  by  boiling  with 
a  soda  solution? 

11.  Why  is  the  solution  blue  when  a  silver  coin  is  dissolved  in 
HN03? 

12.  Why  should  H2O2  be  measured  in  a  glass  graduate? 

13.  Reasoning  from  the  dose  of  liquid  preparations  of  As,  what 
should  be  the  dose  of  solid  preparations? 

14.  When  a  child  is  given  full  doses  of  a  Bi  compound,  what  should 
one  say  to  the  mother  about  the  stools? 

15.  What  is  the  m.p.  of  Pb,  of  Sn,  and  of  soft  solder? 

16.  How  does  aqua  regia  dissolve  Au  and  Pt? 

17.  How  distinguish  "mystery  gold"  from  true  gold? 

18.  What  carat  is  United  States  gold  coin? 

19.  What  is  iron-rust? 

20.  What  is  the  theoretic  m.p.  of  Wood's  fusible  metal? 

21.  Is  an  alloy  of  Au  and  Ag  accompanied  by  expansion  or  con- 
traction? 

22.  What  is  the  weight  of  a  cubic  foot  of  Au? 

23.  Name  five  natural  compounds  of  Al. 

24.  Why  did  the  bronze  precede  the  iron  age? 

25.  What  are  the  chief  uses  of  Pt? 

26.  Compare  Al  and  Sn  for  domestic  purposes. 

27.  What  is  the  sp.  gr.  of  Al,  Cu,  Fe,  Ag,  and  Au? 

28.  Explain  the  chemic  principle  of  "sympathetic  inks." 

29.  How  does  Hg  produce  medicinal  effects? 

30.  Why  are  Ag  salts  used  in  photography? 

31.  Why  does  Cu  turn  green  in  moist  air? 

32.  How  may  taking  S  internally  tarnish  a  silver  dollar  in  the 
pocket  ? 

33.  To  what  is  the  color  of  common  rocks  due? 

34.  What  are  "blacksmiths'  scales"? 

35.  How  do  so  many  ores  occur  as  sulphids? 

36.  Why  are  Fe  salts  often  saccharated? 

37.  Why  are  alloys  generally  preferable  to  single  metals? 

38.  Why  are  sand  and  lime  used  in  the  roasting  and  extraction  of 
metals  ? 

39.  What  are  the  chemic  differences  between  wrought  Fe,  cast  Fe, 
and  steel? 

40.  Why  is  Sb  used  in  type-metal? 

41.  Why  are  Fe  retorts  used  in  separating  Hg  from  other  metals? 

42.  Why  do  dental  fillings  discolor  in  the  mouth? 

43.  Why  is  Fe  administered  in  blood  diseases? 

44.  Why  are  the  alkali  metals  kept  in  benzene? 

45.  Determine  the  carat  of  an  alloy  containing  8  parts  Au,  2  parts 
Ag,  and  2  parts  Cu. 

46.  How  much  pure  gold  must  be  added  to  10  gm.  of  18-carat  gold 
to  raise  it  to  22-carat? 

47.  How  could  you  reduce  10  gm.  of  pure  gold  to  14-carat  ? 

Metalloids. 

1.  What  is  the  most  abundant  element  in  Nature? 

2.  What  is  the  valence,  atomic  weight,  and  density  of  H? 

3.  What  are  the  chief  uses  of  O  in  Nature? 

4.  Give  the  derivation  of  five  elements  named  after  some  physic 
property. 

5.  How  could  you  prove  the  presence  of  H  in  any  compound? 


QUESTIONS.  185 

6.  What  simple  gas  can  be  collected  by  upward  displacement,  and 
which  by  downward  displacement? 

7.  How  detect  decomposition  of  Cl  water  into  HC1? 

8.  What  element  is  noted  for  its  unstable  compounds? 

9.  Describe   the    chief    chemic    interrelation    between    plants    and 
animals. 

10.  To  what  is  the  luminosity  of  P  in  H20  due? 

11.  What  is  the  principal  source  of  P  and  its  compounds? 

12.  Sound  travels  four  times  as  fast  in  H  as  in  0.    Why? 

13.  How  does  Cl  destroy  the  odor  of  sewer-gas? 

14.  State  the  density  and  molecular  weight  of  ozone. 

15.  Name  six  chief  components  of  the  atmosphere. 

16.  How  is  air  liquefied? 

17.  What  difference  between  atmospheric  air  and  that  absorbed  by 
HXD? 

18.  What  danger  of  lead  poisoning  is  there  from  chewing  lead- 
pencils? 

19.  Describe  three  allotropic  forms  of  C. 

20.  Why  is  it  harder  to  light  a  fire  of  coke  or  hard  coal  than  one 
of  soft  coal? 

21.  Write  equation  for  formation  of  S  in  Nature. 

22.  For  what  two  poisonous  metals  has  H  a  great  affinity? 

23.  Name  the  halogens. 

24.  What  is  the  chief  source  of  Br? 

25.  Why  are  C  and  Zn  used  in  batteries? 

26.  How  do  leguminous  plants  restore  the  fertility  of  fields? 

27.  What  is  vulcanized  rubber? 

28.  Why  is  a  partly  burned  match  black? 

29.  Why  is  a  good  draught  needed  for  a  good  fire? 

30.  How  does  charcoal  deodorize? 

31.  Why  does  a  lamp-chimney  smoke  when  the  wick  is  turned  low 
or  too  high? 

32.  How  does  Cl  bleach? 


Oxids. 

1.  What  fractional  part  of  H20  are  O  and  H,  by  weight  and  by 
volume? 

2.  Why  does  boiled  H20  taste  flat? 

3.  Why  is  rain-water  purer  than  that  from  ponds  or  rivers? 

4.  What  are  anhydrids? 

5.  Distinguish   between  deliquescent   and  efflorescent   substances. 

6.  How  does  boiling  soften  water? 

7.  How  does  washing-soda  soften  water? 

8.  To  what  is  the  color  of  most  crystals  due? 

9.  Why  is  natural  water  never  pure? 

10.  How  can  one  make  fire  from  water? 

11.  How  can  one  prove  that  water  is  a  product  of  fire? 

12.  What  are  the  chief  uses  of  Ba02? 

13.  What  advantage  in  using  H3P04  or  H2SO4  rather  than  HC1  in 
preparing  H2O2? 

14.  Write  equation  representing  some  chemic  reaction  into  which 
H20  enters. 

15.  Why  are  halogen  oxids  very  unstable? 

16.  What  is  the  valence  of  I  in  its  oxid? 

17.  Why  is  SCX  always  present  in  city-air? 


186  INORGANIC  CHEMISTRY. 

18.  How  does  S,  thrown  on  the  fire  in  a  stove  or  grate,  extinguish 
the  fire  in  a  burning  flue? 

19.  Is  CO  heavier  or  lighter  than  air? 

20.  What  percentage  of  weight  is  lost  in  converting  magnesium 
carbonate  into  the  oxid? 

21.  How  may  we  render  a  Mg  solution  alkaline  without  precipita- 
tion? 

22.  How  does   calcining  ZnO  for  dental  cements  get  rid   of  con- 
taminating As? 

23.  What  is  the  chemic  composition  of  the  black  scales  on  heated 
Cu? 

24.  What  color  does  red  lead  turn  on  heating,  and  why? 

25.  On  what  does  the  cauterant  action  of  Cr03  depend? 

26.  What  makes  the  stalks  of  grain  stiff? 

27.  What  is  a  grain  of  sand,  chemically  speaking? 

28.  What  is  "petrified  wood"? 

29.  Write  equation  for  preparation  of  laughing-gas. 

30.  How  does  lime  slake? 

31.  Why  does  "soda-water"  effervesce? 

32.  How  does  S02  decolorize  objects? 

33.  What  is  the  chemic  fire-extinguisher? 

Acids. 

1.  Mention  the  general  characteristics  of  hydro-acids. 

2.  What  causes  the  white  film  on  the  inside  of  a  bottle  of  HC1? 

3.  Write  equation  for  reaction  producing  the  white  cloud  when 
the  open  mouths  of  a  bottle  of  HC1  and  of  NH4HO  are  brought  near 
together. 

4.  In  what  part  of  the  human  body  does  free  HC1  occur? 

5.  How  make  official  dilute  HC1  from  the  strong  acid? 

6.  Show  by  equation  how  tree  Cl  is  produced  in  aqua  regia. 

7.  If  a  cold,  dilute  solution  of  starch  and  KI  give  a  blue  color 
with  HC1,  what  impurity  is  indicated? 

8.  What  kind  of  a  stain  is  produced  on  black  cloth  by  HC1,  HN03, 
and  H,S04? 

9.  How  does  dilute  H2SO4  act  as  an  astringent? 

10.  Write  equation  for  reaction  of  HNO3  on  Cu. 

11.  Why  is  HI  usually  prescribed  as  a  syrup? 

12.  Show  by  equations  the  relations  of  the  acids  of  P. 

13.  What  weak  acid  breaks  up  as  soon  as  formed? 

14.  What  acid  is  a  strong  bleaching  and  disinfectant  agent? 

15.  What  is  silicic  acid? 

16.  What  acid  imparts  a  green  color  to  flame? 

17.  If  a  H2S  generator  were  leaking  at  some  point,  how  could  one 
determine  the  point? 

18.  To  what  is  the  bad  smell  of  rotten  eggs  due? 

19.  What  acid  liberates  most  other  acids  from  their  salts? 

20.  Write  equation  for  a  mixture  of  H2S04  and  H20. 

Bases. 

1.  What  are  the  caustic  alkalies? 

2.  WThat  is  the  density  of  NH3?    Is  it  heavier  or  lighter  than  air? 

3.  How  could  you  prepare  the  hydroxid  of  any  of  the  metals  ex- 
cept of  the  alkalies  and  alkaline  earths? 


QUESTIONS.  187 

4.  Calculate  how  many  volumes  of  MH3  are  required  to  make  a 
10-per-cent.  solution,  by  weight,  in  H,O. 

5.  Explain  appearance  of  white  scum  on  lime-water  exposed  to 
the  air. 

6.  Why  is  Ca(HO)2  nearly  twice  as  soluble  in  cold  as  in  boiling 
water? 

7.  What  is  "milk  of  magnesia,"  and  for  what  is  it  used? 

8.  What  hydrate  is  used  extensively  as  a  mordant? 

9.  How  make  "black  wash"  and  "yellow  wash"? 
10.  What  is  dialyzed  iron? 

Salts. 

1.  How  can  one  remove  the  purple  stain  of  AuCl?  from  the  hands? 

2.  Reason  out  a  method  for  removing  AgN03  stains  from  the  skin. 

3.  What  are  the  products  resulting  from  heating  KC103? 

4.  Represent,  by  an  equation,  the  action  of  vinegar  on  chlorinated 
lime. 

5.  Explain  the  color-change  in  identification  of  hypochlorites. 

6.  Which  official  bromid  contains  the  greatest  percentage  of  Br, 
and  hence  is  most  hypnotic? 

7.  Explain  color-change  and  use  of  chloroform  in  Cl  test  for  bro- 
mids.     What  would  a  violet  color  indicate? 

8.  What  amount  of  KI  is  required  to  make  a  saturated  aqueous 
solution? 

9.  Why  is  sugar  used  with  the  licorice-root  in  pil.  ferri  iodid? 

10.  Explain  why  the  protiodid  of  Hg  is  sometimes  yellow  in  color, 
sometimes  green. 

11.  How  detect  the  contaminating  presence  of  red  lead  or  Hg  in 
vermilion? 

12.  How  would  you  prepare  a  solution  of  Ca(SH)2? 

13.  Explain  setting  of  plaster  of  Paris. 

14.  How  much  ZnS04  will  10  gm.  Zn  yield? 

15.  What  change  in  appearance  of  white  lead  and  of  Bi  subsalts 
on  heating  (200°  or  more),  and  why? 

16.  How  detect  adulteration  of  white  lead  with  BaSO4? 

17.  Why  is  good  baking-powder  preferable  to  saleratus? 

18.  Write  equation  for  raising  of  bread  with  baking-powder. 

19.  Why  cannot  NaN03  be  used  in  gunpowder? 

20.  What  should  be  the  color  of  a  mixture  of  bromid  and  iodid 
tested  with  starch  and  Cl  water? 

21.  Mention  the  only  insoluble  Li  salt. 

22.  What   precautions   should   be    observed   in   evaporating   hypo- 
phosphite  solutions? 

23.  What  colored  ppt.  does    (NH4),Mo04  yield  with  a  mixture  of 
phosphates  and  hypophosphites? 

24.  What  pigments  would  you  mix  to  get  chrome-orange? 

25.  Explain  ppt.  of  argols  during  vinous  fermentation. 

26.  Is  FeC2O4  soluble  or  insoluble? 

27.  What  solvents  are  of  aid  in  removing  ordinary  plasters  from 
the  skin? 

28.  How  does  AgNO3  dye  the  hair? 

29.  Why  is  the  caustic  action  of  lunar  caustic  superficial? 

30.  Why  do  dental  cements  give  way  more  rapidly  near  the  gum- 
margin  ? 

31.  Write  equation  for  firing  a  gun. 


188  INORGANIC  CHEMISTRY. 

32.  What  salt  is  formed  in  making  H  in  the  laboratory? 

33.  What  makes  some  waters  hard:  temporary  and  permanent? 

34.  Why  are  ternary  halogen  salts  unstable? " 

35.  Give  the  common  name  and  formula  of  the  chief  salt  of  Sb. 

36.  What  is  the  chemic  nature  of  glass,  and  how  is  it  colored? 

37.  What  changes  take  place  in  the  drying  of  wall-plaster? 

38.  What  group  of  metals  has  the  most  soluble  salts? 

39.  What  is  the  chief  medicinal  compound  of  Mg? 

40.  What  is  the  "bichlorid  of  gold"? 

41.  Write  the  graphic  formula  of  ferric  bromid. 

42.  What  is  the  chief  use  of  the  salts  of  Sn? 

43.  From  what  two  localities  are  Ni  and  Co  -ores  generally   ob- 
tained ? 

44.  What  is  the  only  medicinal  salt  of  Ce? 

45.  Explain  the  use  of  borax  in  welding. 

46.  Why  should  acids  not  be  given  with  calomel? 

47.  How  does  cement  harden  under  H,0? 

48.  Why  does  a  white-painted  house  turn  dark  in  time? 


THE  CARBON  COMPOUNDS. 


THE  term  organic  was  formerly  applied  to  compounds  de- 
rived directly  or  indirectly  from  living  organisms;  all  others 
were  called  inorganic  or  mineral.  This  distinction  was  first 
broken  down  by  Henry  Hennell,  who  in  1826  made  alcohol 
from  coal-gas;  and  again  in  1828  by  Wohler,  who  obtained  urea 
by  warming  ammonium  cyanate  produced  in  the  laboratory. 
Since  then  the  synthetic  manufacture  of  drugs  formerly  prepared 
only  in  Nature's  laboratory  by  the  supposed  "vital  force"  has 
risen  to  immense  proportions.  As  an  example  of  such  synthe- 
sis, acetylene-gas,  C2H2,  can  be  made  by  direct  union  of  C  and 
H  in  the  electric  arc,  ethylene  may  be  prepared  from  acetylene 
by  the  action  of  nascent  H;  and  ethyl  alcohol  is  obtainable  from 
ethylene  by  treating  the  latter  with  H2S04  and  H20.  Ordi- 
narily synthetic  preparations  are  derived  from  natural  products 
and  by-products,  particularly  coal-tar,  which  is  the  source  of  a 
great  number  of  dyes  and  medicines.  It  will  be  seen  that  the 
term  organic  chemistry  has  lost  all  its  former  significance,  and 
is  now  simply  a  convenient  name  for  the  science  of  the  carbon 
compounds. 

Test  for  Organic  Substances  (that  is,  for  Carbon). — Heat  sugar 
or  other  C  compound  on  Pt  foil  till  it  chars.  Keep  heating,  and  it  all 
burns  away  unless  some  impurity  or  a  metallic  salt  of  an  organic  acid 
is  present. 

Treat  sugar  with  H2SO4  and  note  the  charring,  owing  to  the  acid 
taking  H  and  O,  or  water,  away  and  leaving  the  C. 

A  better  test  is  to  mix  the  sugar  with  ten  times  its  weight  of 
CuO  and  heat  to  redness  in  a  narrow  tube  sealed  at  one  end,  passing 
the  gases  (CO2,  etc.)  into  lime-water. 

C  has  a  wonderful  capacity  for  uniting  with  itself  and  H 
to  form  a  great  variety  of  compounds.  Along  with  0,  these  two 
elements  make  up  most  vegetable  substances.  Animal  sub- 
stances contain,  in  addition,  N  and  sometimes  S  and  P,  Cl 
and  I. 

Test  for  H. — Heat  sugar  in  a  dry  test-tube  and  note  cloud  of  vapor 
in  upper,  cooler  part  of  tube. 

Test  for  0. — Show  that  absolute  alcohol  oxidizes  Na,  whereas  ben- 
zene, C6H6,  does  not. 

Test  for  N. — Heat  white-of-egg  disks  on  Pt  foil,  and  note  odor  of 
burning  feathers;  or  heat  in  a  hard-glass  tube  with  soda-lime  (equal 
parts  NaHO  and  CaO)  and  mark  odor  of  NH3. 

(189) 


190  THE  CARBON  COMPOUNDS. 

A  more  delicate  test  is  to  heat  a  small  disk  gradually  to  a  red 
heat  in  a  narrow  test-tube  with  a  piece  of  Na  the  size  of  a  pea.  Allow 
to  cool  a  little,  and  break  off  hot  end  by  immersing  in  a  little  water 
in  an  evaporating-dish.  Then  filter  off  the  C ;  add  a  few  drops  of  FeS04, 
and  warm;  acidulate  with  HC1,  and  test  with  a  drop  of  Fe2Cl6,  forming 
blue  Fe4(FeCy6)3. 

GNaCN  +  Fe  ( HO )  2  =  Na4Fe  ( CN )  6  +  2NaHO 

Test  for  S  by  boiling  white  of  egg  in  an  alkaline  solution  of 
Pb(HO)2,  getting  dark  ppt.  of  PbS. 

Test  for  P  by  fusing  yelk  of  egg  on  Pt  foil  with  KNO3  and  K2C03 
till  the  residue  is  colorless.  Dissolve  this  in  H20,  and,  after  pptg.  sul- 
plates  with  BaCl2,  filter  and  throw  down  phosphates  with  (NHJ2Mo04 
in  HN03. 

We  may  also  oxidize  the  substance  by  heating  in  a  sealed  tube 
with  HN03.  H3PO4  is  formed,  and  is  recognized  by  the  usual  tests. 

Test  chloroform  for  Cl  by  mixing  it  with  pure  CuO  and  igniting 
on  Pt  wire.  Cl  (and  Br)  gives  a  blue  color,  changing  to  green;  I  a  green 
color.  The  wire  should  first  be  held  in  the  flame  till  colorless. 

The  empiric  molecular  formulas  of  organic  substances  are 
obtained  by  dividing  the  percentage  of  each  element  by  its 
atomic  weight  to  get  the  ratio  of  the  elements;  then  taking 
as  many  atoms  of  each  element  in  these  ratios  as  will  make 
up  the  molecular  weight,  which  is  twice  the  vapor-density  (see 
"Analytic  Chemistry"). 

Example. — Formaldehyd  contains  40  per  cent,  of  C,  6.66  per  cent, 
of  H,  and  53.34  per  cent,  of  0.  These  numbers  divided,  respectively,  by 
the  atomic  weight  of  each  element  give  the  proportion  of  3.33  atoms  of 
C,  6.66  of  H,  and  3.33  of  O,  or  2  of  H  to  1  each  of  C  and  0;  hence  the 
percentage  composition  is  CH2O.  The  vapor-density  of  formaldehyd  is 
15;  hence  the  molecular  weight  is  30,  which  corresponds  with  the  weight 
of  the  molecule  CH2O  (12  2  16).  The  correct  formula  is  therefore  CH2O. 

Acetic  acid  shows  the  same  percentage  composition  as 
formaldehyd,  but  its  vapor-density  and  molecular  weight  are 
twice  as  great;  hence  its  formula  should  read  C2H402.  Again, 
lactic  acid  has  the  empiric  formula  C3H603;  since,  while  the 
elements  are  in  the  same  proportion  as  in  formaldehyd,  the 
molecular  weight  is  90  in  place  of  30. 

Organic  compounds  are  separated  and  purified  in  three 
ways:  1.  By  shaking  or  boiling  with  alcohol,  ether,  benzene, 
and  chloroform,  in  all  of  which  inorganic  compounds  are  gen- 
erally insoluble.  A  mixture  of  tartaric  acid,  benzoic  acid,  and 
sugar  can  be  separated,  the  first  by  alcohol,  the  second  by  ether, 
and  the  third  with  H20.  2.  By  crystallization  from  the  various 
solvents  above  mentioned.  Two  or  more  substances  may  some- 
times be  separated  by  fractional  crystallization.  3.  By  distilla- 
tion, especially  fractional,  as  in  the  parting  of  alcohol  and 
water.  The  process  is  sometimes  conducted  in  a  current  of 


HYDROCAKBONS. 


191 


steam  or  under  reduced  pressure.  The  m.p.  of  pure  substances 
is  always  definite;  of  impure  substances  indefinite  and  gradual. 

By  eremacausis  is  understood  the  natural  slow  combustion 
or  decay  of  organic  substances.  Proteins  putrefy  into  bad- 
smelling,,  alkaline  products.  Carbohydrates  ferment  into  C02 
and  other  acid  products  not  usually  of  a  bad  odor. 

Chemic  changes  in  plants  are  generally  constructive,  or 
synthetic;  those  in  animals,,  destructive,  or  analytic.  Thus, 
plants  build  up  C02  and  H20  into  starches  and  sugars,  which 
are  broken  down  again  in  the  animal  organism  into  H20  and 
C02. 

HYDROCARBONS. 

Hydrocarbons  are  simply  compounds  of  C  with  itself  and 
H.  Of  these  there  £re  a  great  number,  some  of  the  most  im- 
portant being  arranged  in  the  following  table.  They  are,  for 
the  most  part,  vegetable  products,  directly  or  indirectly,  ana- 
lytic or  synthetic,  being  built  up  by  plants  from  the  C02  and 
H20  of  the  air. 

NOMENCLATURE  OF  HOMOLOGOUS  HYDROCARBONS. 


SERIES  I. 

SERIES  II. 

SERIES  III. 

SERIES  IV. 

SERIES  V. 

PREFIXES. 

Parnffin.1 
(CnH2n  +  2). 

Olefin* 
(CnH2n). 

Acetylenes 
(CnH2u-2). 

Te.rjtf.nes 
(CnH2n-4). 

Benzenes 
(CnH2n—  6). 

Meth- 

ane  =  CH4 

Eth- 

—  C2He 

ene  or  ylene  =  C2H4 

ine  =  C2H2 

Prop- 

=  C3H8 

"        "      =C3H6 

"  =C3H4 

one  =  C3H2 

But- 

=  C4Hio 

"        "      =  C4H8 

"  =C4H6 

"    =C4H4 

une  =  C4Hs 

Pent- 

=  C5H12 

"        "      =  CsHjo 

"  =  CsH8 

"    =C5H6 

"    =C6H4 

Hex- 

^C^,, 

=  CeH12 

=  C6H10 

-C6H8 

"    =C6H6 

The  arbitrary  arrangement  given  above  is  designed  as  a 
simple  plan  for  designating  hydrocarbons  according  to  their 
exact  composition.  It  will  be  noted  that  the  prefix  meth  indi- 
cates 1  atom  of  C;  eth,  2  atoms;  prop,  3;  but  or  quart,  4;  pent 
or  amyly  5;  hex,  6;  Tiept,  7,  etc.,  with  the  use  of  Greek  numerals. 
It  is  also  seen  at  a  glance  that  the  suffixes  indicating  the  series 
are  in  the  order  of  the  vowels  of  the  alphabet,  and  that  each 
member  of  a  series  is  2  H  less  than  the  corresponding  member 
of  the  preceding  series,  as  shown  in  a  general  way  by  the  alge- 
braic formulas.  Hence  it  is  an  easy  matter  to  deduce  the  name 
from  the  formula,  or  vice  versa.  The  sixth  series  is  known  as 
the  cinnamene;  the  eighteenth  as  the  anthracene. 


192  THE  CARBON  COMPOUNDS. 

Homologous  hydrocarbons  differ  by  CH2,  and  hence  belong 
to  the  same  series.  Isologues  differ  by  H2,  and  are  correspond- 
ing members  of  adjacent  series.  Isomers,  or  metamers,  are 
compounds  having  the  same  composition,  but  different  consti- 
tutions: i.e.,  the  atoms  of  the  molecules  are  not  arranged  in 
the  same  order;  they  have  also  different  physic  properties. 
These  variations  are  accounted  for  by  a  difference  in  the  rela- 
tive positions  of  the  atoms:  i.e.,  the  way  they  face  each  other. 
Stereo-isomerism  is  the  term  applied  to  differences  solely  in 
physic  properties  of  certain  compounds  having  the  same  molec- 
ular and  constitutional  formulas.  The  usual  formula  is  called 
normal  or  primary,  and  has  1  C  linked  to  no  more  than  2  other 
C  atoms.  In  iso,  or  secondary,  compounds  1  C  is  linked  to  3 
others;  in  meso,  or  tertiary,  to  4;  in  neo,  2  to  3.  The  number 
of  possible  graphic  isomeric  formulas  for  the  fourth  member 
of  the  first  series  is  2;  for  the  fifth,  3,  for  the  seventh,  7,  for 
the  eighth,  18,  and  so  on  by  permutation  to  802  for  the  thir- 
teenth member.  Polymeric  compounds  are  multiples,  the  one 
of  the  other:  e.g.,  propene  and  hexene. 

The  members  of  the  first  four  series  are  comparatively 
easily  broken  up,  and  hence  are  arranged  graphically  in  open 
chains,  as  ethane: — 

H     H 

H  — C  — C  — H 

I       I 
H     H 

The  carbon  nucleus  of  the  fifth  series  is  very  permanent,  hence 
is  represented  as  a  closed  chain  or  ring.  The  unsaturated 
nature  of  the  members  of  all  the  series  except  the  first  is  rep- 
resented rationally  by  double  or  treble  bonds  or  linkings  be- 
tween C  atoms;  thus,  ethene: — 

H— r— r— H 

H— L— L— H 

By  dropping  an  H  from  any  of  these  formulas  a  monad 
radical  is  obtained.  Such  hydrocarbon,  alcohol,  or  alkyl  rad- 
icals are  electropositive,  and  are  named  with  the  usual  prefix, 
but  with  the  ending  changed  to  yl  (occasionally  enyl  or  ylene 
when  2  or  3  H  are  removed).  Examples  are:  CH3,  methyl; 
C2H5,  ethyl;  C5H12,  pentyl  or  amyl;  C6H5,  hexyl  or  phenyl. 

PARAFFINS,   OR   FATTY   SERIES. 

This  series  differs  from  the  others  in  its  members  being 
saturated;  hence,  stable.  All  are  neutral,  combustible,  and 
lighter  than  H20.  The  name  paraffin  indicates  "little  affinity," 


HYDROCARBONS.  193 

or  chemic  inertness.  The  first  four  members  of  the  series  are 
gases;  the  next  twelve  oily  liquids  at  ordinary  temperatures; 
the  higher  members  are  fatty  and  waxy  solids.  Atmospheric 
0  converts  many  of  the  liquids  into  solids.  The  members  of 
this  series  are  thought  to  have  originated  by  destructive  dis- 
tillation of  the  fatty  remains  of  sea-animals  in  the  lower  layers 
of  the  earth's  crust. 

Methane,  or  "marsh-gas,"  is  a  colorless,  tasteless,  odorless 
gas  formed  by  decay  of  vegetable  matter  under  H20.  It  con- 
stitutes 90  to  95  per  cent,  of  natural  gas  and  30  to  40  per  cent, 
of  ordinary  coal-gas  (6  to  12  per  cent,  of  water-gas).  It  often 
collects  in  large  quantities  in  ill-ventilated  coal-mines  ("fire- 
damp"), where  it  may  take  fire  and  give  rise  to  terrible  ex- 
plosions. 

Experiment. — Prepare  pure  CH4  by  heating  1  part  NaC2H3O2  with 
4  parts  soda-lime,  collecting  over  H20.  Note  blue  flame  when  burned. 
This  is  a  sign  of  danger  when  seen  within  the  Davy  safety-lamp  of 
miners. 

Ethane  is  also  present  at  times  in  natural  gas.  Butane, 
or  quartane,  is  a  gas  which  when  liquefied  (cymogene)  is  used 
in  ice-machines.  Ehigolene  is  a  hydrocarbon  mixture  used  as 
a  local  anesthetic  by  evaporation. 

Petroleum  is  an  extremely  important  natural  mixture  (up 
to  C16H34)  obtained  from  wells  and  furnishing  most  of  the 
members  of  this  series.  In  the  crude  form  it  is  a  thick,  brown 
or  yellow  liquid.  Among  the  products  of  its  fractional  distilla- 
tion (with  b.p.)  are  cymogene  (0°);  rhigolene  (21°);  benzin 
(50°  to  60°);  gasolene  (75°);  naphtha  (82°  to  149°);  ligroin, 
or  light  petroleum;  cleaning  oil  (120°  to  170°);  kerosene,  or 
refined  petroleum  (150°  to  250°);  mineial  sperm-oil  (218°); 
lubricating  oil  (301°);  paraffin  (melts  at  45°  to  65°);  vaselin 
(soft,  melts  at  40°  to  45°;  hard,  at  45°  to  51°);  and  coke,  or 
petroleum  pitch.  All  fractions  are  purified  by  treating  with 
H2S04,  then  washing,  then  rendering  alkaline.  Some  of  these 
compounds  are  derived  from  the  dry  distillation  of  soft  coal, 
bitumen,  shaly  wood,  ozokerite,  and  fish-oil.  Petroleum  com- 
pounds are  characterized  generally  by  more  or  less  fluorescence. 
They  are  soluble  in  ether,  chloroform,  CS2,  benzin,  benzene, 
turpentine,  and  oils. 

Benzin,  benzolin,  or  petroleum-ether  (mixture  of  pentane 
and  hexane)  has  a  sp.  gr.  of  0.67  and  is  a  good  solvent  for  oils, 
fats,  resins,  and  rubber.  It  remains  semiliquid  at  175°.  It  is 
used  to  remove  grease-spots  and  for  varnishes  and  paints. 
Clothing  saturated  with  benzin  may  take  fire  in  direct  sun- 
light. 

13 


194  THE  CARBON  COMPOUNDS. 

Naphtha  appears  in  three  forms  (A,  B,  and  C),  with  differ- 
ent b.p's.  It  is  the  so-called  safety-oil,  and  is  used  as  a  solvent 
for  oils,  fats,  resins,  and  rubber.  Cleaning  oil,  as  the  name 
suggests,  is  used  for  cleaning  purposes  and  also  in  place  of  tur- 
pentine in  varnishes.  Gasolene  is  highly  inflammable,  and  is 
used  in  special  stoves  and  for  running  automobiles. 

Kerosene,  or  coal-oil,  should  not  "flash"  (yield  an  inflam- 
mable-gas) below  120°  F.  or  ignite  itself  under  300°  F. 

Experiment  to  Test  Flashing-point  of  Kerosene. — Fit  a  large  test- 
tube  with  a  perforated  cork  provided  with  a  bent  glass  tube  and  a 
thermometer.  Pour  about  15  c.c.  of  kerosene  into  the  tube,  and  heat 
very  gradually.  Agitate  surface  of  liquid  at  frequent  intervals  by 
blowing  through  glass  tube;  then  apply  a  flame  to  mouth  of  test-tube, 
repeating  the  trial  until  the  flame  flashes  down  into  the  tube. 

Vaselin,  cosmolin,  or  petrolatum,  is  a  mixture  of  the  upper 
half-series  of  fatty,  yellowish  hydrocarbons.  It  is  purified  and 
decolorized  by  passing  through  bone-black.  Liquid  petrolatum 
(sp.  gr.,  0.875  to  0.945)  is  a  useful  sedative  application  to  mu- 
cous membranes.  The  solid  (hard  and  soft)  is  used  as  an  oint- 
ment-base. 

Paraffin  (sp.  gr.,  0.877)  is  the  waxy  residue  left  after  dis- 
tilling off  the  above-named  products.  Ozokerite,  or  mineral 
wax,  consists  largely  of  paraffin,  and  is  used  in  the  preparation 
of  ceresin,  a  substitute  for  wax.  Paraffin  is  acted  on  hardly  at 
all  by  the  strongest  chemicals,  for  which  reason  it  is  used  on 
the  glass  corks  of  reagent  bottles.  It  is  also  utilized  exten- 
sively for  candles. 

Photogene  and  solar  oil  are  distilled  from  the  tar  left  after 
the  destructive  distillation  of  cannel-coal  or  shale  in  the  pro- 
duction of  paraffin.  They  are  used  as  solvents  and  illuminants. 

Coal-gas  is  made  by  the  destructive  distillation  at  bright- 
red  heat  of  bituminous  coal  in  fire-clay  or  cast-iron  retorts. 
The  gaseous  products  are  passed  through  the  hydraulic  main, 
a  series  of  tubes  partly  filled  with  H20,  where  the  steam,  tar, 
and  NH3  are  condensed;  then  into  the  scrubbers  (columns  of 
coke  over  which  water  trickles);  then  through  a  number  of 
large  boxes  with  perpendicularly  arranged  shelves,  where  the 
gas  is  purified  (of  H2S,  C02,  CS2,  S02,  and  volatile  oils)  with 
freshly  slaked  lime,  a  mixture  of  sawdust  and  oxid  of  Fe,  etc.; 
and  thence  to  the  gasometer,  a  large,  tub-shaped,  iron  storage- 
vessel,  floated  upside  down  on  water.  A  ton  of  coal  yields 
10,000  to  12,000  cubic  feet  of  gas.  The  specific  gravity  of  coal- 
gas  is  from  0.65  to  0.75. 

Water-gas  is  made  by  the  alternate  action  of  air  and  steam 
on  anthracite  coal  at  a  red  or  white  heat.  The  gaseous  product 


HYDROCARBONS. 


195 


is  mixed  with  naphtha-vapor,  strongly  heated  in  tubular  re- 
torts, and  purified  as  above.  Being  cheaper,  though  much  more 
poisonous  (four  or  five  times  as  much  CO)  it  is  very  largely 
used  for  heating  and  illuminating  purposes.  The  chief  ingre- 
dients in  both  kinds  of  gas  are  CO  (5  to  25  per  cent.),  H  (30 
to  50  per  cent.),  CH4  (20  to  40  per  cent.),  C2H2,  C2H4  (4  to  10 
per  cent.),  N,  and  C02. 

The  by-products  in  the  manufacture  of  coal-gas  are  of  vast 
importance,  particularly  NH3  and  coal-tar.     About  150  more 


Fig.  29.— Manufacture  of  Coal-gas. 

or  less  valuable  chemic  compounds  are  obtained  in  this  way. 
They  are  separated  by  differences  in  solubility,  b.p.,  sp.  gr.,  or 
chemic  reaction. 

Experiment. — Heat  sawdust  in  an  ignition-tube,  and  notice  in- 
flammable gas,  tar,  charcoal,  and  acetic  acid. 

Natural  gas  is  chiefly  CH4,  with  some  C2H6,  C3H8,  H,  etc. 
It  is  probably  a  product  of  past  decomposition  of  organic  matter 
pptd.  from  water  in  stratified  rocks  and  subjected  to  heat  and 
pressure.  The  C02  of  springs  and  soils  may  have  originated  in 
the  same  way. 

OLEFINS,   OE   ETHYLENE   SERIES. 

This  series  is  comparatively  unimportant.  Its  members 
are  prepared  by  destructive  distillation  of  fats,  waxes,  coal,  and 


196  THE  CARBON  COMPOUNDS. 

lignite.  The  first  three  are  gases,  the  following  four  volatile 
liquids,  and  the  sixteenth  and  higher  solids.  They  are  mostly 
soluble  in  ether  and  alcohol,  and  are  readily  oxidized  by  Cr03 
or  K2Mn208.  The  principal  member  is  ethylene  (C2H4),  or 
olefiant  gas,  so  called  because  it  forms  a  colorless,  oily  liquid 
(C2H4C12)  with  Cl;  this  fact  also  accounts  for  the  name  of  the 
series.  About  6  per  cent,  of  coal-gas  consists  of  C2H4,  to  which 
the  luminosity  is  largely  due.  It  has  a  peculiar,  sweet  smell. 
Pentene,  or  amylene,  has  been  used  as  an  anesthetic  under  the 
name  of  pental.  It  is  obtained  by  dehydrating  amyl  alcohol, 
and  has  an  odor  like  mustard. 

ACETYLENES. 

This  series  is  so  named  after  ethine,  or  acetylene,  a  color- 
less gas  with  a  sharp,  garlicky  odor,  formed  by  incomplete  com- 
bustion when  a  lamp  or  gas-jet  is  turned  low.  It  is  prepared 
commonly  by  decomposition  of  CaC2  with  H20. 

Experiment. — To  some  lumps  of  calcium  carbid  add  water,  and 
light  evolved  gas. 

It  has  ten  times  the  illuminating  power  of  ordinary  gas, 
and  is  not  so  poisonous,  but  may  explode  when  mixed  with  air. 
On  heating  it  is  converted  into  benzene  (C6H6)  or  styrene 
(C8H8).  Propine  is  commonly  known  as  allylene  and  allene 
(isomeric  gases),  and  butine  as  crotonylene. 

TERPENES,   OK   TRITONES. 

This  series  comprises  most  oleoptens  or  essential  oils  of 
plants,  used  for  odor  and  flavor,  and  obtained  generally  by  dis- 
tillation, sometimes  by  pressure,  fermentation,  or  solution  in 
fixed  oils.  They  leave  no  permanent  stain  on  paper,  being 
volatile.  They  are  mostly  lighter  than  H20  and  quite  soluble 
in  alcohol,  strong  solutions  being  termed  essences,  weaker  solu- 
tions (10  per  cent.)  spirits.  They  are  fairly  soluble  in  ether, 
but  in  H20  only  to  the  extent  of  1  m.  per  fluidounce,  forming 
aquae.  Many  of  them  are  isomeric  or  polymeric  with  turpen- 
tine, C10H16,  and  they  tend  to  polymerize  to  C15H24  or  C20H32 
when  heated  in  a  sealed  tube  or  shaken  with  H2S04. 

The  crude  oil  of  turpentine,  the  juice  of  the  pine,  when 
distilled  leaves  common  rosin,  which  is  used  in  some  official 
plasters.  The  sp.  gr.  of  turpentine  is  0.86.  It  is  a  good  solvent 
for  resins,  paints,  S,  and  P.  On  exposure  to  air,  like  other  vola- 
tile oils,  it  absorbs  0  as  ozone,  and  becomes  resinous,  which 
explains  its  drying  action  in  paints.  The  acid,  or  French  tur- 


HYDROCARBONS.  197 

pentine,  thus  obtained  is  used  as  an  antidote  for  P  poisoning. 
Terebene,  terpin,  and  terpinol  are  valuable  medicinal  deriva- 
tives of  C10H16.  They  are  stimulants  because  they  are  volatile. 
When  C10H16  is  treated  with  H2S04  white  crystals  of  terpin 
hydrate,  C10H16.3H20,  are  formed. 

Volatile  oils  may  be  classified  as  follows: — 

1.  True  terpenes  (C10H16):    Bergamot,  birch,  chamomile, 
caraway,  dill,  hops,  juniper,  lemon,  myrtle,  nutmeg,  orange, 
parsley,  pepper,  rue,  savin,  thyme,  Tolu,  turpentine,  and  vale- 
rian. 

2.  Cedrenes,  or  sesquiterpenes  (C15H24):    Calamus,  casca- 
rilla,  cedar,  cloves,  cubebs,  patchouly,  and  rosewood. 

3.  Aromatic  aldehyds:   Almond  and  cinnamon. 

4.  Compound  ethers:   Mustard  and  wintergreen. 

The  third  and  fourth  classes  are  a  little  heavier  than  H20. 
Most  essential  oils  contain  also  some  oxidation  products  in  the 
form  of  stearoptens. 

Caoutchouc  is  a  hard,  tough  polyterpene,  soluble  in  CS2, 
C6H6,  chloroform,  and  ether.  When  heated  with  7  to  10  per 
cent,  of  S  at  130°  to  150°  it  yields  black,  vulcanized  rubber, 
which  is  more  elastic  and  less  affected  by  chemic  agents.  Hard 
rubber  (vulcanite,  ebonite)  contains  from  20  to  35  per  cent,  of 
S.  Dental  rubber  is  colored  with  vermilion,  ZnO,  CaC03,  and 
white  clay.  Eubber  plasters  have  as  a  basis  cleansed  and  rolled 
Para  rubber  with  olibanum  (true  frankincense),  purified  pitch, 
etc.  When  they  become  brittle  and  non-cohesive,  they  can  be 
temporarily  restored  by  warming  and  wetting  with  alcohol. 

Gutta-percha  is  harder  and  more  tenacious,  and  can  be 
molded  in  hot  water  into  splints.  A  solution  in  chloroform  is 
known  as  traumaticin,  and  is  used  as  a  dressing  for  slight 
wounds.  Gutta-percha  is  also  employed  by  dentists  as  a  plastic 
filling  material. 

Stearoptens,  or  camphors,  are  solid,  volatile,  oxidized  es- 
sential oils,  therefore  insoluble  in  H20,  but  soluble  in  alcohol. 
They  burn  with  a  smoky  flame,  like  all  the  rest  of  this  series, 
and  are  medicinally  stimulants.  Camphor  has  the  formula 
C10H160  (that  of  Borneo,  C10H180).  Monobromated  camphor, 
C10H15BrO,  is  made  by  adding  Br  to  a  solution  of  camphor  in 
chloroform.  Menthol,  from  oil  of  peppermint;  thymol,  from 
oil  of  thyme  and  horsemint;  and  eucalyptol,  from  oil  of  euca- 
lyptus, are  similar  to  camphor  chemically  and  are  characterized 
by  a  pleasant  odor.  Artificial  camphor  is  a  direct  combination 
of  HC1  vapor  and  C10H16. 

Experiment. — Make  artificial  camphor  by  passing  HC1  gas  through 
10  or  20  c.c.  of  oil  of  turpentine,  and  collect  ppt.  on  filter. 


198  THE  CARBON  COMPOUNDS. 

Eesins  are  solid,,  brittle,  amorphous,  non-volatile,  oxidized 
essential  oils;  acid  in  reaction;  soluble  in  alcohol,  ether,  and 
oils;  and  pharmaceutically  incompatible  with  H20.  Oleoresins 
contain  also  some  unoxidized  oil,  and  are  soluble  in  ether  and 
alcohol.  Balsams  are  like  oleoresins,  with  addition  of  benzoic 
or  cinnamic  acid,  which  gives  an  aromatic  odor.  Alcohol  is 
their  best  solvent.  Gum-resins  are  resins  plus  gum  and  sugar 
and  up  to  9  per  cent,  of  volatile  oil.  They  appear  in  milky 
tears,  .and  are  best  dissolved  with  dilute  alcohol.  Eubbed  with 
H20  in  a  mortar,  they  yield  good  emulsions  (asafetida,  white; 
scammony,  green;  gamboge,  yellow).  Many  members  of  the 
above  classes  are  natural  vegetable  exudations. 

Examples  of  Resins. — Rosin,  ergotin,  guaiac,  jalap,  pyrethrum, 
podophyllum,  lac  (stick,  seed,  and  shell),  sumbul,  mastic,  sandarac, 
copal,  amber,  and  asphalt.  The  last  three  are  fossil  resins. 

Examples  of  Oleoresins. — Copaiba,  capsicum,  cubeb,  lupulin,  pepper, 
ginger,  male  fern,  crude  turpentine,  Burgundy  and  Canada  pitches,  wood- 
oil  or  gurjun  balsam,  and  various  turpentines  from  pine-,  fir-,  and  larch- 
trees.  The  medicinal  ones  are  extracted,  as  a  rule,  with  ether  (100  to 
150  parts).  Wood-tar  (pix  liquida)  is  a  complex  mixture  containing 
methyl  alcohol,  acetone,  paraffin,  pyroligneous  and  carbolic  acids,  etc., 
prepared  by  the  destructive  distillation  of  pines. 

Examples  of  Gum-resins. — Ammoniac,  asafetida,  myrrh,  scam- 
mony, galbanum,  gamboge,  euphorbium,  and  olibanum  (frankincense). 

Examples  of  Balsams. — Benzoin,  Peru,  copaiba,  Tolu,  and  styrax. 
Benzoin  is  one-eighth  to  one-fourth  benzoic  acid. 

Eesinous  compounds  are  much  used  in  medicine  as  purga- 
tives and  as  mucous-membrane  stimulants.  The  common  resins 
are  also  employed  in  making  varnishes,  lacquers,  and  sealing- 
wax.  Common  rosin  saponifies  fat,  and  is  used  in  making  cheap 
soaps.  The  rosin  oil,  obtained  by  destructive  distillation,  is 
used  with  lamp-black  and  sealing  wax  in  preparing  printers' 
ink. 

Identification  of  Rosin,  or  Colophony. — Boil  a  little  of  the  powder 
with  4  times  as  much  HN03;  when  cold,  dilute  with  an  equal  amount  of 
water  and  add  NH4HO,  getting  a  blood-red  coloration. 

Experiment. — Show  how  alcoholic  solution  of  guaiac  is  colored 
blue  by  CrO3  or  other  oxidizing  agents. 


AROMATIC,   OR   BENZENE,   SERIES. 

The  chief  member  of  this  series  is  benzene,  or  benzol, 
C6H6,  a  colorless,  very  volatile  liquid,  with  peculiar  odor;  sp. 
gr.,  0.884;  insoluble  in  H20,  and  derived  from  coal-tar — the 
light  oil  that  floats  on  water.  It  is  very  inflammable,  and  a 
good  solvent  for  I,  P,  S,  fats,  oils,  and  resins.  From  it  are 


HYDROCARBONS.  199 

derived  most  modern  antiseptics,  antipyretics,  and  dyes.     Its 
molecule  is  a  symmetric  hexagon:  — 


. 

f 

C 


H—  C       C—  H 

II        I 

H—  C       C—  H 

\/ 

C 

I 

TT 


Experiment. — Make  C6H6  by  heating  a  mixture  of  CaO  and  dry 
benzoic  acid,  passing  vapors  into  a  test-tube  set  in  ice. 

Toluene,  C7H8;  xylene,  C8H10;  and  cumene,  C9H12,  are 
also  found  in  coal-tar.  Cymene,  C10H14,  occurs  in  oil  of  thyme, 
and  is  closely  related  to  the  terpenes,  and  can  readily  be  ob- 
tained from  them  by  dehydrogenation  with  Br  or  I. 

Two  or  more  benzene  nuclei  may  be  grouped  together. 
Several  uncondensed  nuclei  are  present  in  the  diphenyl,  di- 
phenyl-methane,  triphenyl-methane,  and  indigo  groups. 

Naphthalene,  C10H8,  popularly  known  as  "coal-tar  cam- 
phor/' or  "tar  balls,"  is  constituted  of  two  molecules  of  benzene 
condensed  into  one,  as  shown  by  this  graphic  formula: — 


II 

H 

1 

1 

C 

C 

/  \  /  \ 

H  —  C 

C 

C  — 

H 

II 

1 

1 

H  —  C 
\ 

C 

^  \ 

C  — 

f 

H 

\  4 
C 

\  t 
C 

1 

1 

II 

H 

Anthracene  (the  basis  of  alizarin,  or  artificial  madder),  and 
phenanthrene,  C14H10,  contain  three  condensed  molecules  of 
benzol: — 


200  THE  CARBON  COMPOUNDS. 

H          H          H 

I  I  I 

c       c       c 


H— C         C          C         C— H 

I          II  I  I 

H— C         C          C         C— H 

\/-vx  \/ 

c       c       c 

I         I         I 

H          H          H 

HYDROCARBON   DERIVATIVES. 

These  are  of  two  main  classes:  1.  The  fatty,  or  aliphatic, 
compounds  of  the  first  series,  arranged  in  open  chains.  2.  The 
aromatic,  or  ring,  compounds  of  the  fifth  series.  In  both  of 
these  groups  the  derivatives  are  produced  "by  substitution  of 
other  elements  or  radicals  for  one  or  more  atoms  of  H  in  the 
hydrocarbon.  Hence  they  are  called  substitution  derivatives. 
Addition  derivatives  are  formed  by  direct  union  of  unsaturated 
(second,  third,  and  fourth  series)  hydrocarbons  with  elements 
or  radicals. 

When  the  C  ring  of  benzene  is  broken  by  substitution  of 
N  for  C,  we  have  the  pyridin  group  of  compounds  (quinolin  by 
similar  substitution  in  naphthalene;  acridene  from  anthracene); 
by  0  for  C  in  furfuran  group;  by  S  for  C  in  thiophen  com- 
pounds. 

Pyrrol.                        Furfuran.  Thiophen.  Pyrazalon. 

H  — C  — C  — H  H  — C  — C  — H  H  — C  — C  — H  H2C  — CH 

II       II                             II       II  II       II                          I       II 

H  — C     C  — H  H  — C      C  — H  H  — C      C  — H  OC      N 

\/  \/  \/  \/ 

N  — H  O  S  NH 

The  relations  of  hydrocarbon  derivatives  are  shown  most 
clearly  by  graphic  formulas,  substituting  characteristic  radicals 
for  H  in  methane  and  in  benzene. 

Hydrocarbons. 

Methane  =  CH4.  Benzene  =  C6H6. 

H  — p  — H  /H 

H  — L  — H  C 

//    \ 
H— C       C— H 

H_i  <5_H 
v 


HYDROCARBONS.  201 

Halogen  Derivatives. 

Methyl  chlorid  =  CH3C1.  Phenyl  chlorid  =  C6H5C1. 

H— r  — Cl  Cl 

H  — L  — H 


SulpJionic  Compounds. 
Replace  one  H  with  HSO3. 

Alcohols,  or  Hydrates. 

Methyl  hydrate  =  CH3HO.  Benzyl  alcohol  =  C6H5CH2HO. 

H— p  — HO  CHHO 

H  — L  — H 


Ethers,  or  Oxids. 

Methyl  oxid  =  ( CH3  )2O.  Benzoquinone  =  C6H4O2 

H—  r\          r\         r\—  H 


EC-0--GI 


TJiio-etJiers  and  Alcohols. 

Contain  S  instead  of  O. 

Aldehyds  (fundamental  group  =  COHr). 

Methyl  aldehyd  =  CH3COH.  Benzaldehyd  =  C6H5COH. 

H-o-^COH  xCOH 

H  — L  — H 


Ketones  (fundamental  group  =  CO11 ), 

Di-methyl  ketone  (acetone)  Di-phenyl  ketone  ( benzophenone ) 

=  (CH3)2CO.  =CHCO>  F 


Organic  Acids  (fundamental  group  =  COOHi ). 

Acetic  acid  =  CH3COOH.  Benzoic  acid  =  C6H-COOH 

H-p-COOH 
H  —  \j  —  H 


202  THE  CARBON  COMPOUNDS. 

Ammonia  Derivatives:     Amins  (H  replaced  by  basic  radical)  and  amids  (H 
replaced  by  acid  radical). 

Metbylamin  =  CH3NH2.  Phenylamin  (anilin)  =  C6H5NH2. 

H  — r  — NH2 
H  — L  — H 


Carbohydrates. 
Sugar  and  starch  groups  of  aldebyds  and  ketones. 

Phenols  (HO  replaces  H  in  C6H6). 
,HO 


Phenyl  bydrate  (carbolic  acid)  =C6H5HO. 

Quinones  (substitute  benzene  compounds  —  2O  for  2  H). 


Benzoquinone  =  C6H402. 

Nitrogen  Derivatives  (fundamental  groups  :  — NO2,  nitro;  — NO,  nitroso  ;  and 
—  N —  OH,  isonitroso  derivatives). 

Methyl  nitrite  =  CH3NO2  (an  ester).  Nitrobenzene  =  C6H5NO2 

H-r-No2 

H  —  v>  —  H 


Carbonyl  Derivatives  (fundamental  group  =  COn  ). 
Cyanogen  Derivatives  (fundamental  group  =  CNI). 

Azo  and  Diazo  Compounds.     The  diad  group   — N  =  N —   is  linked  on  both 

sides  to  a  hydrocarbon  radical  in  azo,  to  an  acid  radical 

and  a  hydrocarbon  radical  in  diazo. 

Hydrazins.     Aromatic  substitution  derivatives  of  NH2  —  NH2. 
Alkaloids  and  Ptomains.     Chiefly  derivatives  of  pyridin  and  quinolin. 

Proteins.     Phosphines  (alkyl  substitution  products  of  PH3. )     Arsinea  (same 
of  As2O3).    Stibines  (same  of  Sb2O3). 


ALKYL,  OR  ETHEREAL  SALTS.  203 

The  arrangement  of  isomeric  phenyl  derivatives  in  ortho 
(1  and  2),  meta  (1  and  3),  and  para  (1  and  4)  compounds  is 
shown  below  [C6H4(HO)2],  Dihydroxy-benzene: — 

Pyrocatechin.  Resorcin.  Hydroquinone. 

HO  HO  HO 


HO 


HO 


ALKYL,  OR  ETHEREAL  SALTS. 

Cl  and  Br  can  act  directly  on  hydrocarbons,  replacing  H; 
I  acts  indirectly.  The  halogen  derivatives  comprise  many  gen- 
eral and  local  anesthetics.  They  have  a  sweet,  ethereal  odor 
and  taste,  and  are  more  or  less  volatile  and  soluble  in  alcohol 
and  ether,  and  generally  insoluble  in  H20.  They  are  liable  to 
decompose  in  the  light,  setting  free  the  halogen. 

Methyl  chlorid,  CH3C1,  is  prepared  by  heating  CH3HO 
with  a  mixture  of  NaCl  and  H2S04.  CH4  and  Cl  unite  in  sun- 
light to  form  CH3C1.  It  is  a  colorless,  combustible  gas,  liquefy- 
ing at  22°  or  with  5  atmospheres'  pressure.  In  the  liquid  form 
it  is  used  as  a  refrigerant  local  anesthetic. 

Ethyl  chlorid,  C2H5C1,  is  a  colorless  liquid  used  as  a  local 
anesthetic.  Its  solution  in  alcohol  is  known  as  chloric  ether. 

Ethyl  bromid  is  a  heavy,  colorless  liquid,  boiling  at  39°. 
It  has  been  used  as  a  general  anesthetic. 

By  far  the  most  important  halogen  derivative  is  chloroform 
(trichlormethane),  CHC13.  It  is  prepared  by  the  action  of  chlo- 
rinated lime  on  ordinary  alcohol  or  acetone  or  (the  purest)  from 
chloral. 

Experiment. — Make  CHC13  by  mixing  in  a  test-tube  retort  chlorin- 
ated lime  with  x/4  as  much  acetone  and  3  times  as  much  H2O,  and  then 
distilling  on  the  water-bath  into  a  beaker.  The  chloroform  collects  as  a 
heavy,  oily  liquid  at  the  bottom  of  the  beaker,  and  is  separated  and 
washed  with  H2S04,  treated  with  Na2C03,  and  redistilled  over  CaO. 

2C3H0O  +  3Ca02Cl2  =  2CHC13  +  2Ca(HO)2  +  Ca(C2H3O2)2 

Chloroform  is  a  limpid,  caustic  liquid;  sp.  gr.,  1.49;  b.p., 
60°.  It  tends  to  decompose  in  light  or  heat,  setting  free  Cl 
and  HC1  and  the  poisonous  compound  carbonyl  chlorid,  COC12. 
Pure  CHC13  evaporates  without  residue,  is  neutral  to  litmus, 
and  gives  no  ppt.  with  AgN03  nor  darkens  with  KHO  or  H2S04. 
One-half  to  1  per  cent,  alcohol  is  allowable,  and  renders  CHC13 
more  stable. 


204  THE  CARBON  COMPOUNDS. 

Experiment. — Test  some  of  the  prepared  CHC13  by  heating  with  a 
drop  each  of  alcoholic  solution  KHO  and  anilin.  The  offensive  odor  of 
phenyl-carbylamin,  C6H5NC,  is  produced. 

Test  another  portion  by  boiling  with  a  few  drops  of  KHO  and  a 
fragment  of  resorcin,  getting  an  intense-red  coloration  of  rosolic  acid. 
Chloral  shows  both  of  these  reactions,  but  has  a  different  odor. 
Paper  dipped  in  CHC13  burns  with  a  green  mantle,  and  HC1  is  given  off. 

CHC13  is  a  good  solvent  for  I,  P,  resins,  camphor,  alka- 
loids, caoutchouc,  and  fats,  but  its  chief  use  is  as  an  anesthetic, 
for  which  purpose  it  should  always  be  administered  with  plenty 
of  air  or  0.  The  spirit  is  10  per  cent,  in  strength.  The  water 
is  a  weak,  but  saturated,  solution  prepared  by  shaking. 

lodoform  (triiodo-methane),  CHI3,  is  prepared  by  the 
action  of  I  on  alcohol  or  acetone  in  the  presence  of  alkalies. 
It  appears  in  microscopic,  light-yellow  crystals  with  strong  saf- 
frony  odor.  It  sublimes  readily,  and  melts  at  119°.  It  is  sol- 
uble in  oils,  alcohol,  ether,  and  CHC13.  Its  antiseptic  effect 
depends  on  the  liberation  of  I  (of  which  it  contains  96  per  cent.) 
in  presence  of  moisture. 

Experiment. — Make  CHI3  by  dropping  a  few  crystals  of  I  into  quite 
dilute  alcohol  and  then  adding  KHO  drop  by  drop,  warming  gently,  till 
the  red  color  just  disappears.  When  sediment  has  settled,  examine  crys- 
tals under  microscope.  On  a  large  scale  K2CO3  with  heat  is  emploved  in- 
stead of  KHO. 

C2H5HO  +  4L  +  6KHO  =  CHI3  +  KCHO2  +  SKI  +  5H20 

Aristol  is  an  odorless  substitute  for  CH3,  and  is  a  com- 
bination of  iodin  and  thymol,  containing  46  per  cent,  of  the 
former.  Europhen,  isobutyl-orthocresol  iodid,  is  another  sub- 
stitute. 

Bromof orm,  CHBr3,  is  a  colorless  liquid,  prepared  similarly 
to  CHI3.  It  resembles  CHC13  and  is  used  as  a  sedative,  par- 
ticularly in  coughs. 


ALCOHOLS. 

These  are  hydrates  of  hydrocarbon  radicals.  According  to 
the  number  of  HO  groups,  they  are  termed  monatomic  (mono- 
hydric),  diatomic  (glycols),  triatomic  (glycerins),  etc.,  up  to 
nonatomic.  They  are  also  classified  as  primary,  secondary 
(carbinols),  and  tertiary,  each  being  characterized  by  the  funda- 
mental group  (CH^OH)1,  (CH.OH)11,  and  (C.OH)111,  respect- 
ively. The  lower  members  are  liquids,  the  higher  solids. 
Alcohols  are  readily  oxidized:  primary  to  aldehyds  and  mono- 
basic acids,  secondary  to  ketones,  and  tertiary  to  simple  com- 
pounds:— 


ALCOHOLS.  205 

CH2.OH  -f  0  =  H20  -f-  COH          COH  +  0  =  COOH 
CH.OH  +  0  =  H20  -f  CO 

Experiment. — Add  a  few  crystals  of  CrO3  to  5  c.c.  of  absolute  alco- 
hol until  the  vinegar  odor  of  acetic  acid  is  noted. 

Alcohols  are  neutral,  but  it  is  possible  to  replace  the  H  of 
HO  with  a  metal,  forming  alcoholates,  such  as  C2H5ONa.  Pri- 
mary monatomic  alcohols  are  the  most  important,  and  are 
derived  from  the  saturated  hydrocarbons  of  the  first  series. 

Methyl  alcohol  (carbinol,  wood-spirit),  CH3HO,  is  present 
in  the  oil  of  wintergreen,  but  is  prepared  chiefly  by  the  de- 
structive distillation  of  wood  and  as  a  by-product  in  beet-sugar 
manufacture.  Its  sp.  gr.  is  0.8;  b.p.,  66°.  It  mixes  with  H20 
in  all  proportions.  Its  vapor  is  explosive.  CH3HO  is  a  solvent 
for  fats,  oils,  camphor,  and  resins,  and  is  used  in  the  manu- 
facture of  varnishes  and  organic  dyes,  for  heating  purposes,  and 
in  the  preparation  of  methylated  spirit  (90  per  cent,  raw  spirit, 
10  per  cent,  wood  spirit).  The  disagreeable  odor  and  taste  of 
commercial  CH3HO  are  due  to  tarry  impurities. 

The  official  alcohol  is  ethyl  hydrate,  C2H5HO  (methyl  car- 
binol, CH3.CH2HO).  It  occurs  in  diabetic  urine,  and  is  formed 
by  alcoholic  fermentation  of  glucoses:  C6H1206  =  2C2H5HO 
-(-  2C02.  The  fermented  product  is  purified  by  distillation 
over  dehydrating  agents,  such  as  CaCl2,  CaO,  CuS04,  or  wood- 
ashes.  Absolute  alcohol  contains  less  than  0.5  per  cent.  H20. 
It  boils  at  78.5°  and  freezes  at  —130°.  Its  sp.  gr.  is  0.7937. 
Absolute  alcohol  is  a  transparent  mobile  liquid,  very  hygro- 
scopic; hence  it  dehydrates  tissues  and  is  used  to  harden  his- 
tologic  and  pathologic  specimens  for  the  microtome.  For  the 
same  reason  it  is  antiseptic,  preventing  decay  and  coagulating 
albumin.  Alcohol  is  a  good  solvent  for  resins,  alkaloids,  and 
volatile  oils.  It  burns  with  a  non-luminous  flame.  Ordinary 
alcohol  (sp.  gr.,  0.82)  is  94-per-cent.  strength  by  volume;  the 
dilute  (sp.  gr.,  928),  48.6  by  volume,  41  per  cent,  by  weight 
(52  +  48  =  96.3). 

Experiment. — Show  that  ordinary  alcohol  contains  H2O  Dy  adding 
to  it  some  white  anhydrous  CuSO4.  Explain  color-change. 

Alcohol  is  a  stimulant  in  small  doses,  and  depressant  and 
narcotic  in  large.  In  the  system  it  is  burned  partly  (1  Y2  or 
2  oz.  daily)  into  C02  and  H20,  the  remainder  passing  off  un- 
changed. In  spite  of  this  fuel  action,  it  is  not  strictly  a  food. 
It  causes  accumulation  of  fat  through  decrease  of  activity  and 
is  not  stored  in  the  body. 


206  THE  CARBON  COMPOUNDS. 

Experiment.— Make  C2H5HO  by  adding  a  little  brewer's  yeast  to 
a  solution  of  5  gm.  commercial  glucose  in  200  c.c.  H20.  Let  the  flask 
stand  in  a  warm  place  for  a  day,  then  distil  and  collect  a  few  c.c.  of 
the  liquid.  Test  distillate  by  adding  half  as  much  H2S04  and  an  equal 
volume  of  K2Cr2O7  solution.  Aldehyd  is  formed  and  is  recognized  by  its 
peculiar  odor;  the  liquid  turns  green  by  formation  of  Cr2(S04)3.  The 
iodoform  test,  already  described,  may  also  be  employed. 

Alcoholic  liquors  are  classified  as  malt-products,  wines,  and 
spirits.  Malt-liquors  include  beer,  ale,  stout,  and  porter.  These 
are  formed  by  diastatic  and  alcoholic  fermentation  of  malted 
barley.  The  ferment  diastase  in  the  grain  on  warming  develops 
dextrin  and  maltose;  then  yeast  is  added  to  set  up  alcoholic 
fermentation.  These  malt-liquors  contain  2  to  8  per  cent,  of 
alcohol  (beer  weakest,  ale  strongest);  also  C02  and  malt-sugar. 
Hops  are  added  to  beer  as  a  preservative,  and  glycerin  to  cause 
foam.  Hard  cider  contains  about  5  per  cent,  of  alcohol. 

Wines  are  prepared  from  grapes  fermented  by  the  action 
of  a  living  ferment  always  present  on  grape-stalks  and  in  the 
air.  If  only  the  must,  or  grape-juice,  is  used  a  white  wine 
(official,  10  to  14  per  cent.)  results;  if  the  marc,  or  skins  and 
seeds,  is  included,  a  red  wine  (same  strength  as  white).  The 
"ripening"  of  wine  in  casks  takes  from  two  to  eight  years. 
Champagne  and  other  effervescing  wines  are  bottled  before 
fermentation  is  quite  complete,  with  addition  of  alcohol  and 
cane-sugar.  The  alcoholic  strength  of  wines  varies  from  5  per 
cent,  for  light  Ehine  to  18-25  per  cent,  in  sherry  and  port. 
These  strong  wines  are  usually  fortified  by  addition  of  spirit. 

Spirits  are  liquors  distilled  from  grains,  potatoes,  beets, 
rice,  etc.,  that  have  been  mixed  with  malt  and  then  yeast. 
Brandy,  or  cognac,  is  produced  by  distillation  of  wines;  rum 
from  fermented  cane-molasses;  whisky  from  corn,  rye,  barley, 
and  potatoes;  arrack  from  fermented  rice;  pulque  from  the 
cactus.  Gin  is  common  grain-spirit  distilled  with  juniper  ber- 
ries. Bay-rum  is  prepared  by  distilling  rum  with  leaves  of 
myrcia  acris  and  other  plants. 

Spirits  contain  from  40  to  45  per  cent,  of  alcohol.  Dis- 
tilled, or  "raw,  spirit"  is  rectified  by  charcoal  filtration  and 
redistillation  to  84  per  cent.,  by  weight  ("spirit  of  wine").  The 
most  concentrated  alcohol  by  simple  distillation  is  91  per  cent, 
by  weight,  94  per  cent,  by  volume.  Alcoholimetry,  the  testing 
of  strength  of  alcohols,  is  based  upon  sp.  gr.  tables. 

The  oily  liquid,  amyl  alcohol  (C-H^HO),  is  the  chief  in- 
gredient of  fusel  oil,  a  mixture  of  higher  homologs  present 
largely  in  raw  spirit  and  separated  by  fractional  distillation, 
C2H5HO  distilling  over  at  a  lower  temperature.  The  bad  taste 
and  intoxicating  effects  of  poor  quality  ardent  spirits  are  due, 


ALCOHOLS.  207 

in  great  measure,  to  fusel  oil.  Alcohol  containing  fusel  oil 
darkens  on  shaking  with  H2SO4.  Pyronic  aldehyd,  or  furfurol, 
is  a  convulsant  poison  present  in  vermouth  and  bitters.  Ab- 
sinthe contains  nine  different  essences,  all  toxic. 

The  tertiary  isomer  of  amyl  alcohol,  amylene  hydrate 
[dimethyl-ethyl-carbinol,  (CH3)2.COH.C2H5]  is  a  colorless,  oily 
liquid,  soluble  in  water  and  in  alcohol,  and  used  as  an  hypnotic. 

The  higher  monatomic  alcohols  are  fatty  and  waxy  solids. 
Cetyl  alcohol,  C16H33HO,  is  the  chief  component  of  spermaceti. 
Melyssyl  alcohol,  C30H61HO,  is  present  in  bees-wax.  Cholesteric 
alcohol,  C26H43HO,  is  the  only  free  alcohol  normally  present 
in  the  human  body.  It  is  the  principal  ingredient  of  gall- 
stones. 

The  primary  diatomic  alcohols,  or  glycols,  are  derived  from 
olefins,  and  are  of  no  practical  interest.  They  are  sweet,  syrupy 
liquids.  The  simplest  one  is  glycol: — 

CH2— OH 
CH2— OH 

The  primary  triatomic  alcohols,  or  glycerins,  are  of  great 
interest  and  importance.  Ordinary  glycerin,  or  propyl  hydrate 
[C3H5(HO)3]  occurs  very  abundantly  in  Nature,  making  up, 
in  conjunction  with  fatty  acids,  the  bulk  of  vegetable  and  ani- 
mal fats  and  oils,  from  which  it  is  liberated  by  treating  with 
alkalies.  It  is  a  by-product  in  alcoholic  fermentation  and  in 
the  manufacture  of  soap  and  stearic  acid.  The  sp.  gr.  of  glyc- 
erin is  1.25;  it  boils  at  290°.  It  is  very  hygroscopic,  absorbing 
twice  its  volume  of  H20,  and  thus  depleting  congested  tissues. 
Glycerin  is  insoluble  except  in  alcohol  and  water.  It  is  an  ex- 
cellent solvent  for  I,  Br,  starch,  carbolic  acid,  alum,  borax,  and 
tannin,  such  solutions  being  often  termed  glycerites. 

In  some  respects  it  is  preferable  to  syrups  as  a  sweetening 
agent,  since  it  does  not  ferment.  It  is  also  an  excellent  ex- 
cipient  for  fluid  extracts.  Plasmas  are  non-fatty  ointment  sub- 
stitutes or  paints  consisting  principally  of  glycerin  and  water 
thickened  into  a  gelatinous  mass  with  starch,  gelatin,  isinglass, 
and  other  agents.  Most  medicated  gauzes  and  cottons  contain 
a  small  quantity  of  glycerin  or  oil  and  resin  to  keep  them  soft 
and  promote  the  action  of  the  medicinal  agents.  The  "soft 
gelatin"  capsules  for  liquids  contain  glycerin. 

Boroglycerin,  C3H5B03,  is  made  by  heating  H3B03  with 
one  and  one-half  times  as  much  glycerin.  It  is  used  as  an 
antiseptic. 


208  THE  CARBON  COMPOUNDS. 

Experiment. — Test  for  glycerin  with  borax  bead.  The  green  flame 
is  due  to  free  boric  acid:  — 

C3H5(HO)3  +  Na2B407  —  H3B03  +  2NaBO2  +  C3H5BO3 

On  heating  glycerin  with  H2S04  the  characteristic  irri- 
tating odor  of  acrolein  is  evolved. 

Grlycerophosphoric  acid  is  a  yellow,  syrupy  liquid  prepared 
by  mixing  1  part  of  H3P04  with  1 1/2  parts  of  glycerin,  and 
gradually  heating  to  190°.  Both  the  acid  and  its  salts  are  used 
as  nervine  remedies  and  to  aid  nutrition. 

The  hexatomic  alcohols — mannite,  dulcite,  and  sorbite — 
have  the  formula  C6H1206.  The  first  is  derived  from  manna- 
ash,  the  second  from  Madagascar  manna,  and  the  third  from 
the  berries  of  the  mountain-ash.  They  resemble  sugar  in  taste, 
but  do  not  ferment  or  reduce  metallic  solutions. 


ETHERS. 

Simple  ethers  are  oxids  of  hydrocarbon  radicals;  if  the 
radicals  are  unlike,  the  ether  is  termed  mixed.  A  compound 
ether,  or  ester,  is  an  oxid  of  a  hydrocarbon  radical  and  an  acid 
radical:  in  other  words,  a  salt  of  an  acid  radical.  Ethers  are 
generally  formed  by  the  dehydrating  action  on  alcohols  of 
H2S04  or  by  combination  of  other  acids  with  alcohols.  The 
compound  ethers  have  usually  a  pleasant  and  refreshing  odor. 
They  give  the  bouquet,  or  flavor,  to  alcoholic  liquors,  where  they 
are  generated  by  age,  and  they  are  the  chief  constituents  of 
fruit-essences,  fats  and  fixed  oils,  bees-wax  (melyssyl  palmitate), 
and  spermaceti  (cetyl  palmitate).  Bees-wax  (cera  flava)  is 
bleached  (cera  alba)  by  exposure  to  light  and  air  or  by  the  use 
of  H202.  It  is  used  in  candles.  All  ethers  are  neutral.  The 
lower  members  are  volatile  liquids;  the  higher,  non-volatile 
solids.  Esters  are  decomposed  by  alkalies,  which  combine  with 
the  acid  radical,  setting  free  the  alcohol.  Artificial  fruit-flavors 
consist  chiefly  of  butyrates,  acetates,  and  salicylates  of  ethyl, 
methyl,  and  amyl  in  glycerin  and  water. 

Ordinary  ether  is  ethyl  oxid  [(C2H5)20],  sometimes  called 
sulphuric  ether  because  H2S04  is  used  in  its  manufacture. 

Experiment. — Make  ether  by  mixing  in  a  flask  10  c.c.  of  alcohol, 
5  c.c.  of  H2S04,  and,  after  cooling,  distilling  over  the  ether  at  about 
140°  into  a  stoppered  bottle.  Take  great  care  not  to  bring  the  vapors 
into  contact  with  the  flame. 

C2H5HO  +  H2S04  =  C2H5HSO4  (sulphovinic  acid)   +  H2O 
C2H5HSO4  +  C2H5HO=  (C2H5)2O  +  H2S04 

On  a  large  scale  the  process  is  made  continuous  by  allowing  alcohol  to 
flow  into  the  flask  at  the  same  rate  as  distillation.    The  product  is  puri- 


ETHERS.  209 

fied  by  mixing  with  oxid  and  ehlorid  of  Ca,  pouring  off  the  clear  liquid 
after  settling,  and  distilling. 

The  official  ether  contains  96  per  cent,  of  (C2H5)20  and  4 
per  cent,  of  C2H5HO.  It  is  a  colorless,  mobile,  and  very  vola- 
tile liquid,  with  characteristic  odor,  burning  taste,  and  neutral 
reaction;  sp.  gr.,  0.726;  b.p.,  37°.  It  is  soluble  in  10  volumes 
of  H20  and  in  alcohol,  chloroform,  petroleum  liquids,  and  fixed 
and  volatile  oils,  and  is  itself  a  good  solvent  for  fats,  fixed  oils, 
and  gun-cotton  (collodion).  It  burns  readily  with  a  luminous 
flame,  and  gives  off  a  combustible  vapor. 

Experiment. — Show  inflammability  of  ether  by  applying  a  flame  to 
a  dram  of  it  in  a  dish.  Note  the  initial  explosion  and  rapid  combustion. 

Ether  is  used  by  inhalation  as  a  general  anesthetic,  being 
less  depressing,  but  more  irritating,  than  CHC13. 

Test  for  Purity  of  Ether. — Water  is  detected  by  turbidity  when 
shaken  with  an  equal  volume  of  CS2;  alcohol  by  shaking  with  anilin- 
violet,  which  colors  ether  adulterated  with  alcohol. 

The  spirit  and  compound  spirit  of  ether  consist  of  about  1 
part  of  ether  and  2  parts  of  alcohol;  the  latter  spirit  contains 
2  1/2  per  cent,  of  ethereal  oil,  which  is  a  mixture  of  equal  vol- 
umes of  ethyl  sulphate  (heavy  oil  of  wine)  and  ether. 

Acetic  ether,  C2H5.C2H302,  is  a  colorless,  mobile  liquid  of 
a  pleasant,  acetous,  and  fruity  odor  and  generally  soluble. 

Experiment. — Prepare  ethyl  acetate  by  warming  alcohol  with  half 
as  much  again  each  of  H2S04  and  NaC2H3O2.  Note  odor  and  write  equa- 
tion. 

Methyl  salicylate,  CH3.C7H503,  is  identic  with  oil  of  betula 
and  the  essential  constituent  of  oil  of  wintergreen.  It  is  pre- 
pared by  distilling  a  mixture  of  methyl  alcohol,  salicylic  acid, 
and  H2S04. 

Xitrous  ether,  C2H5.N02,  is  made  by  distilling  a  mixture 
of  C2H5HO,  H2S04,  and  NaN02.  Sweet  spirit  of  niter  contains 
4  parts  of  this  ether  with  96  of  alcohol. 

Nitroglycerin  [C3H5(N03)3]  is  prepared  from  glycerin  and 
sulphuric  and  nitric  acids.  It  is  a  yellow  liquid,  slightly  sol- 
uble in  alcohol;  the  1-per-cent.  solution  is  known  as  spirit  of 
glonoin.  Nitroglycerin  is  very  explosive  when  struck  or  heated 
to  257°.  The  products  of  such  an  explosion  are  shown  by  the 
following  equation: — 

4C3H5(N03)3  =  12C02  +  10H20  +  6N2  +  02 

These  four  gases  occupy  a  space  about  18,000  times  as  great 
as  that  of  the  original  explosive.    When  used  for  this  purpose 


210  THE  CARBON  COMPOUNDS. 

it  is  generally  mixed  with  some  dry,  inert  powder  (charcoal, 
silica,  and  sawdust)  and  sold  as  dynamite,  or  giant  powder. 

Amyl  nitrite,  CgH^NO,,,  is  prepared  in  the  same  way  as 
ethyl  nitrite,  except  that  amyl  alcohol  is  used  in  place  of  ethyl 
alcohol.  It  is  a  pale-yellow  liquid,  with  the  strong,  peculiar 
odor  of  amyl  compounds,  and  is  used  by  inhalation  as  a  quick 
stimulant. 

Amyl  acetate,  C5H11C2H302  ("essence  of  pear"),  is  used  by 
confectioners  as  a  flavoring  agent. 

Salol,  or  phenyl  salicylate,  C6H5.C7H503,  is  prepared  by 
heating  salicylic  acid  in  an  atmosphere  of  C02,  whereby  it  loses 
H20  and  C02.  It  occurs  in  white,  faintly  aromatic  crystals, 
generally  soluble  except  in  water.  Taken  internally,  it  is 
broken  up  in  the  duodenum  into  phenol  and  salicylate.  The 
same  change  takes  place  when  salol  is  combined  with  caustic 
hydroxids. 

Experiment. — Dissolve  a  little  salol  by  warming  with  liquor  po- 
tassae.  Add  excess  of  HC1,  and  note  odor  of  phenol  and  ppt.  of  salicylic 
acid  in  silky  needles. 

Salacetol  is  a  substitute  for  salol,  from  which  it  differs  by 
having  the  radical  acetol,  C3H50,  in  place  of  C6H5.  Betol,  or 
#-naphtol  salicylate  (C6H4OHCOOC10H7),  is  a  white,  crystal- 
line powder  used  as  an  intestinal  antiseptic. 

Salophen,  or  acetyl-para-amido-phenyl  salicylate,  is  an- 
other derivative  of  salol  in  which  an  atom  of  H  in  phenyl  is 
replaced  by  the  univalent  group  NHCOCH3.  It  is  split  up  by 
the  fat-cleaving  ferment  of  the  pancreas  into  salicylic  acid  and 
para-amido-phenol,  which  is  much  less  toxic  than  the  simple 
phenol  into  which  salol  is  partly  converted. 


ALDEHYDS. 

These  compounds  are  formed,  as  the  name  suggests,  by 
dehydrogenation  of  alcohols,  usually  by  oxidation;  for  exam- 
ple, C2H5HO  —  H2  =  CH3COH  (ethyl  aldehyd).  The  group 
COH  is  characteristic  of  all  aldehyds.  They  are  intermediate 
between  alcohols  and  acids,  and  are  neutral  in  reaction. 

Formaldehyd  (methyl  aldehyd),  HCOH,  is  obtained  by 
passing  air  and  vapors  of  CH3HO  over  a  heated  spiral  of  Pt 
or  Cu: — 

CH3HO  +  0  =  H.COH  +  H20 

It  is  a  colorless  gas  with  a  pungent  odor.  A  40-per-cent.  solu- 
tion in  H20  is  known  as  formalin,  and  is  largely  used  for  gen- 
eral antisepsis  in  1/4-  to  2-per-cent.  solution.  Its  affinity  for 


ALDEHYDS.  211 

H20  causes  it  to  act  as  an  escharotic  in  strong  solutions,  and 
accounts  for  its  value  in  sterilizing  catgut  and  hardening  ana- 
tomic specimens.  Formaldehyd-vapor  is  coming  into  extensive 
use  for  disinfecting  rooms,  either  by  special  apparatus  or  by 
hanging  up  sheets  wet  with  formalin.  HCOH  does  not  injure 
cloth  fabrics,  but  its  action  is  more  superficial  than  that  of 
S02. 

Paraformaldehyd,  (HCOH)3,  is  the  triple  polymer  of  for- 
maldehyd,  produced  by  slow  evaporation  of  the  latter  in  CH3- 
HO.  It  is  a  crystalline  solid,  insoluble  in  H20.  On  heating 
it  breaks  up  into  3  molecules  of  HCOH,  and  is  very  convenient 
for  sterilizing  instruments  in  this  way. 

Acetic,  or  ethyl,  aldehyd,  CH3.COH,  is  ordinary  aldehyd, 
obtained  from  C2HrHO  by  oxidation  with  K2Cr207  in  presence 
of  H2S04:- 

4H2S04  +  K2Cr207  +  C2H5HO  =  CH3.COH  + 
Cr2(S04)3  +  K2S04  +  5H20  +  02 

Experiment. — Place  in  a  large  flask  2  parts  of  K2Cr2O7  and  6  parts 
of  H20,  and  then  pour  in  carefully  through  stop-cock  funnel  a  mixture 
of  equal  parts  of  C2H5HO  and  H2SO4,  and  warm  gently.  Note  the  peculiar 
fragrance  of  aldehyd  evolved.  Now  adapt  a  cork  and  a  long,  bent,  glass 
tube  and  distil  slowly  into  another  test-tube.  Boil  a  portion  of  dis- 
tillate with  KHO  and  get  a  brown-yellow,  resinous  mass.  Let  the  other 
portion  stand  for  a  day  or  two,  when  it  will  be  found  acid,  and,  on 
neutralizing  with  Na2CO3,  boiling,  and  adding  H2SO4,  the  characteristic 
odor  of  acetic  acid  is  noted:  — 

CH3.COH  +  O  =  CH3.COOH 

Paraldehyd  is  the  triple  polymer  of  aldehyd,  obtained  by 
the  action  of  the  ferment  emulsin  in  presence  of  H20.  It  is 
solid,  soluble  in  8.5  H20,  and  used  as  an  hypnotic  in  elixirs. 

Trichloraldehyd,  or  chloral,  CC13.COH,  is  a  simple  substi- 
tution derivative  of  aldehyd,  prepared  by  saturating  cold  alco- 
hol with  Cl  (forming  chloral  alcoholate),  then  warming  to  the 
b.p.,  and,  after  cooling  and  shaking  with  H2S04,  distilling  the 
lower  liquid  layer  at  94°  to  99°.  Chloral  is  a  colorless,  oily 
liquid  with  a  sharp  odor  and  acrid  taste.  Its  hydrate,  CC13.- 
COH.H20  is  a  valuable  hypnotic,  obtained  by  the  simple  addi- 
tion of  H20.  Chloral  hydrate  appears  in  white  crystals,  soluble 
in  all  the  common  solvents.  It  liquefies  when  mixed  with 
stearoptens  or  phenol,  and  is  incompatible  with  alkalies. 

Experiment. — Heat  chloral  hydrate  with  KHO,  and  note  odor  of 
chloroform. 

Benzaldehyd,  C6H5.COH,  is  the  oil  of  bitter  almond, 
formed  by  decomposition  of  the  glucosid  amygdalin  through 


212  THE  CARBON  COMPOUNDS. 

the  action  of  the  ferment  enmlsin  in  presence  of  H20.  It  is 
a  colorless,  oily  liquid  with  bitter,  burning  taste  and  character- 
istic aromatic  odor.  The  crude  oil  contains  HCN.  Aqua 
amyg.  amarse  has  1  part  of  the  oil  in  1000  of  water.  Salicylic, 
cinnamic,  cuminic,  anisic,  and  vanillic  aldehyds  are  derived 
from  the  corresponding  oils  (salicylic  from  salicin). 


ACETALS, 

These  compounds  are  formed  by  union  of  alcohol  and  alde- 
hyds, with  elimination  of  water.    Methylal 


is  a  mobile,  colorless  liquid  of  aromatic  odor,  freely  miscible 
with  solvents,  and  used  in  medicine  as  an  hypnotic.  Acetal  is 
similar  in  physic  properties. 


KETONES, 

As  already  stated,  these  compounds  are  formed  by  oxida- 
tion of  secondary  alcohols,  and  are  characterized  by  the  group 
CO11.  Like  the  aldehyds,  they  are  neutral  and  tend  to  polym- 
erize, but  do  not  reduce  ammoniacal  silver  solutions  as  do  the 
former.  On  oxidation  they  split  into  two  acids. 

The  only  important  ketone  is  acetone,  or  dimethyl-ketone, 
(CH3)2CO.  It  is  often  present  in  distinct  quantity  in  diabetic 
urine,  and  is  a  product  of  the  distillation  of  carbohydrates.  It 
is  prepared  technically  by  dry  distillation  of  Ca(C2H302)2,  the 
carbonate  remaining.  It  is  a  liquid  of  pleasant,  minty  odor 
and  sharp  taste,  soluble  in  water,  alcohol,  and  ether.  It  gives 
the  iodoform  test,  the  same  as  alcohol.  Its  principal  uses  are 
as  a  solvent  for  resins  in  varnishes  and  as  a  source  of  CHC13, 
CHI3,  sulphonal,  and  trional.  It  is  also  administered  internally 
in  5-  to  15-drop  doses  as  an  alterative  and  anthelmintic. 

Oil  of  rue  is  chiefly  methyl-nonyl  ketone,  C9H19.CH3.CO. 
Hypnone,  or  acetophenone,  is  phenyl-methyl  ketone,  C6H5.- 
CH3.CO.  Chloretone 

CH3 

I 
CC13  — C  — OH 

I 
CH3 


ORGANIC  ACIDS.  213 

is  an  hypnotic  and  local  anesthetic  formed  by  adding  KHO  to 
equal  weights  of  chloroform  and  acetone,  and  distilling  with 
steam. 

ORGANIC  ACIDS. 

Organic  acids  are  characterized  by  the  fundamental  group 
carboxyl,  COOH1,  replacing  H  in  hydrocarbons.  They  are 
monobasic,  dibasic,  or  tribasic  according  to  the  number  of  car- 
boxyl  groups.  By  replacing  H  of  COOH  with  metals  various 
salts  are  formed.  The  term  acid  radical  signifies  the  residue 
of  the  acid  left  after  subtracting  HO.  These  differ  from  alkyl 
or  alcohol  radicals  in  containing  0.  Acids  may  be  considered 
hyclroxids  of  acid  radicals,  and  their  anhydrids  oxids  of  acid 
radicals.  The  organic  acids  include  both  solids  and  liquids, 
generally  colorless.  The  variously  colored  scale  compounds  are 
generally  solutions  of  fresh  metallic  hydrates  (Fe  particularly) 
in  organic  acids  or  acid  salts,  said  solutions  being  dried  on 
glass  plates. 

The  fatty-acid  series  of  saturated  monobasic  acids  have 
the  general  empiric  formula  CnH2n02.  The  higher  members 
occur  abundantly  with  glycerin  in  natural  oils  and  fats  and 
with  monatomic  alcohols  in  waxes. 

Formic  acid,  H.COOH,  occurs  in  ants  (formica  rufa), 
bristles  of  stinging  nettles,  and  fir-cones,  as  well  as  in  perspira- 
tion, urine,  and  muscle-plasma.  In  the  venom  of  bees  and 
hornets  it  is  united  to  C^H^.  It  may  be  obtained  by  heating 
oxalic  acid  in  presence  of  glycerin,  or  by  oxidation  of  methyl 
alcohol: — 

CH3HO  -f  02  =  H.COOH  +  H20 

Formic  acid  is  a  colorless  liquid  with  sharp  odor  and  irritating 
action  on  skin. 

Experiment. — Warm  H.COOH  gently  with  a  few  drops  of  H2SO4. 
The  latter  acid  removes  H20,  and  CO  is  evolved,  as  proved  by  burning; 
no  ppt.  with  lime-water. 

Acetic  acid,  CH3.COOH,  is  found  in  various  plant-juices, 
partly  free  and  partly  combined  with  K  and  Ca.  It  is  formed 
during  the  decay  of  many  organic  substances,  and  is  commonly 
manufactured  by  "acetic  fermentation"  or  slow  oxidation  of 
weak  alcoholic  liquors  (trickling  over  wood-shavings  in  perfo- 
rated casks)  or  by  the  dry  distillation  of  wood.  The  fermented 
product  is  ordinary  vinegar,  which  contains  4  to  10  per  cent, 
of  acetic  acid.  The  wood-product,  known  as  pyroligneous  acid, 
is  neutralized  with  milk  of  lime,  the  tarry  impurities  are  roasted 


214: 


THE  CARBON  COMPOUNDS. 


away,  and  then,  after  treating  with  HC1,  the  liquid  is  dis- 
tilled. Acetic  acid  is  strongly  acid,  with  a  distinct  vinegar 
odor.  It  is  a  solvent  for  resins  and  camphor,  and  is  used  largely 
in  manufacturing  organic  dyes.  The  glacial  acid,  so  called  be- 
cause it  crystallizes  below  17°,  is  over  99  per  cent,  absolute, 
and  is  used  as  a  caustic.  The  official  acid  contains  36  parts  by 
weight  of  the  acid  and  64  of  H20;  the  dilute  is  of  6-per-cent. 


Fig.  30. — Quick  Vinegar  Process. 

strength.  It  is  a  curious  fact  that  the  highest  sp.  gr.  (1.074) 
of  acetic  acid  is  that  of  78-per-cent.  strength  (acid  combined 
with  1  molecule  H20).  Dilute  acetic  acid  neutralized  with 
(NH4)2C03  forms  spirit  of  ammonium  acetate:  a  valuable  dia- 
phoretic. Acetates  are  neutral  and  soluble  in  water,  except 
some  basic  salts. 

Experiment.— Heat  some  NaC2H3O2  with  a  drop  or  two  of  H2SO4 
and  note  vinegar  odor. 


ORGANIC  ACIDS.  215 

Carefully  neutralize  HC2H302  and  add  solution  of  Fe2Cl6. 
A  deep-red  color  results,  and  on  boiling  a  reddish-brown  ppt. 

Trichloracetic  acid,  CC13.COOH,  is  formed  by  oxidation  of 
chloral  with  HN03.  It  is  a  crystalline  caustic  and  ppts.  albu- 
min. 

Propionic  acid,  C2H5.COOH,  is  so  called  because  it  is  the 
first  acid  (protos,  pion)  which  can  be  separated  in  an  oily  layer 
by  adding  CaCl2,  etc.  It  is  a  liquid  with  a  peculiar  odor,  and 
is  present  in  sweat  and  urine. 

Butyric  acid,  C3H7.COOH,  is  the  characteristic  acid  of 
butter,  where  it  exists  free  when  rancid,  as  also  in  feces  and 
sweat.  It  is  a  liquid,  differing  from  higher,  common,  fat  acids 
in  being  soluble  in  H20. 

Of  the  two  valeric,  or  valerianic,  acids,  C4H9.COOH,  the 
150  is  the  more  important.  It  has  the  odor  of  valerian,  and  is 
found  in  this  root  and  angelica.  It  is  also  a  product  of  albu- 
minous decomposition;  hence  is  present  in  old  cheese  and  hu- 
man excrement.  It  is  usually  obtained  by  oxidation  of  amyl 
alcohol.  It  is  an  oily,  colorless  liquid,  and  is  soluble  in  alcohol. 

Caproic  acid,  C5H1:L.COOH,  is  present  in  goat-butter; 
myristic,  C14H2802,  in  nutmegs  and  cocoa-nuts;  and  caprylic 
in  Limburger  cheese  and  cocoa-nut  oil.  Enanthylic  acid, 
C7H1402,  is  present  in  oxidized  castor-oil,  and  has  an  agreeable 
odor.  Pelargonic  acid,  C9H1802,  is  found  in  geranium-leaves; 
lauric,  C12H2402,  in  cocoa-nut  oil;  arachidic,  C20H4002?  in  pea- 
nuts; bycenic,  C22H4402,  in  oil  of  ben;  cerotic,  C27H5402,  in 
small  grains  free  in  bees-wax;  and  melissic,  C30H6002,  in  bees- 
wax. True  cerates  always  contain  wax.  The  soap-like  decom- 
position that  dead  bodies  sometimes  undergo  is  due  to  forma- 
tion of  adipocere,  the  NH4  and  Ca  salts  of  cerotic  acid.  Stearin 
candles  are  a  mixture  of  palmitic  (HC16H3102)  and  stearic 
(HC1RH3502)  acids,  both  white,  smooth  solids. 

Of  the  unsaturated,  monobasic  acids  of  the  olefin  series, 
oleic,  C17H33.COOH,  is  most  important.  It  is  a  constituent  of 
fixed  oils,  and  a  by-product  in  the  manufacture  of  candles.  It 
is  a  colorless,  oily  liquid;  tasteless,  neutral  (unless  exposed  to 
air);  sp.  gr.,  0.9;  insoluble  in  H20  only  (oleates  of  K  and  Na 
dissolve  in  H20).  HN02  changes  oleic  acid  to  crystalline  elai- 
din,  and  it  solidifies  spontaneously  below  15°.  It  forms  oleates 
with  metallic  oxids  and  alkaloids.  Eicinoleic  acid  is  an  isomer 
of  oleic.  Angelic  acid  is  in  the  root  of  the  same  name.  Erucic 
acid  is  present  in  oil  of  mustard. 

Diatomic  acids  have  the  general  composition  CnH2n03  and 
may  be  considered  diatomic  alcohols  in  which  one  HO  is  re- 
placed by  COOII. 


216  THE  CARBON  COMPOUNDS. 

Glycolic  acid,  CH2.OH.COOH,  is  a  white,  crystalline  solid 
found  in  unripe  grapes  and  leaves  of  the  wild  grape. 

Lactic  acid,  C2H4OH.COOH,  is  present  in  opium,  ensilage, 
sauer  kraut,  gastric  juice,  and  the  gray  matter  of  brain.  It  is 
produced  by  lactic  fermentation  of  sugar  (sour  milk,  koumiss, 
kefir).  The  official  acid  is  75-per-cent.  strength.  It  is  a  color- 
less, odorless,  syrupy  liquid;  sp.  gr.,  1.2;  generally  soluble. 
Sarcolactic,  or  paralactic,  acid  is  found  in  muscles  (more  after 
work),  extract  of  beef,  blood,  and  sometimes  urine.  It  differs 
from  ordinary  lactic  acid  only  in  its  action  on  polarized  light. 

Identification  of  Lactic  Acid. — A  few  drops  of  acid  added  to  very 
weak  solution  of  Fe2Cl6  gives  a  distinct  yellow  color. 

Oxalic  acid  [H2C204.2H20(COOH.COOH)]  is  found  in 
many  plants,  as  dock  and  wood-sorrel  (Oxalis  acetosella)  in  the 
form  of  the  K  salt;  in  rhubarb,  beets,  etc.,  as  the  Ca  salt.  It 
is  prepared  artificially  by  oxidizing  starch  or  sugar  with  HN03, 
or  by  fusing  cellulose  (sawdust)  with  caustic  K  or  Na.  It  is  a 
white,  very  sour,  crystalline,  poisonous  solid,  freely  soluble  in 
water,  less  so  in  alcohol.  It  is  used  as  a  mordant  in  calico- 
printing,  to  clean  Cu,  as  a  solvent  for  Fe  stains,  and  a  precipi- 
tant for  Au  and  Pt.  The  Ca  salt  is  very  insoluble,  and  often 
gives  rise  to  urinary  calculi. 

Experiment.  —  Make  ink  by  mixing  clear,  aqueous  solutions  of 
tannin  and  FeS04j  and  decolorize  with  clear  solution  of  H2C204. 

Succinic  acid,  H2C4H404,  occurs  in  amber  (succinum),  lig- 
nite, and  unripe  grapes.  It  appears  in  colorless  prisms  with 
acrid  taste,  more  soluble  in  water  than  in  alcohol.  It  is  seda- 
tive and  diuretic. 

Malic  acid,  H2C4H405  (oxysuccinic),  is  widely  distributed 
in  the  vegetable  kingdom  in  unripe  grapes,  apples,  quinces, 
currants,  gooseberries,  rhubarb,  etc.  It  appears  in  hygroscopic 
needles.  The  laxative  effect  of  fresh  cider  is  due  to  malic  acid. 

Tartaric  acid,  H2C4H406,  occurs  in  four  isomeric  forms, 
namely:  meso-,  levo-,  and  dextro-  tartaric  and  racemic  (para- 
tartaric)  acids.  The  common  dextro-acid  is  obtained  from 
grape-juice,  where  it  is  both  free  and  in  combination  with  K 
and  Ca.  The  pure  acid  appears  in  colorless,  monoclinic  prisms 
of  acid  taste,  soluble  in  H20  and  alcohol.  On  strongly  heating, 
it  chars  quickly,  giving  off  a  distinct  caramel  odor.  It  is  used 
in  calico-printing  and  by  confectioners  to  prevent  crystallization 
of  sugar. 

Identification  of  Tartaric  Acid. — Neutral  solutions  give  a  white 
ppt.  with  CaCl2,  soluble  (after  quickly  collecting  on  filter  and  washing) 
in  KHO,  but  pptd.  on  boiling. 


ORGANIC  ACIDS.  217 

The  basis  of  granular  effervescent  salts  is  a  mixture  of 
NaHC03  (83  to  85  parts)  with  a  slight  excess  of  citric  (70)  or 
tartaric  (75  parts)  acid  and  sugar.  They  are  combined  by  heat- 
ing a  little  above  b.p.  or  by  moistening  and  stirring  mixed  pow- 
ders with  alcohol,  making  the  granules  even  by  sifting  after 
drying.  Ninety  grains  of  the  finished  salt  equal  a  teaspoonful. 

The  tribasic  acid,  citric,  H3C6H507,  occurs  free  in  lemons 
(6  per  cent.),  currants,  cranberries,  raspberries,  and  gooseber- 
ries. The  Ca  salt  is  present  in  wood,  potatoes,  and  beets.  The 
acid  appears  in  large,  colorless  crystals,  readily  soluble  in  H20. 

Of  the  aromatic  acids,  benzoic  and  salicylic  are  most  im- 
portant. They  are  both  sublime  substances,  antiseptics,  and 
preservatives,  Benzoic  acid,  HC7H502(C6H5.COOH),  occurs  in 
gum  benzoin  and  the  urine  of  herbivora.  It  is  manufactured 
from  toluene  by  treating  with  Cl,  then  H20.  It  appears  in 
large  needles,  sparingly  soluble  in  cold  water,  but  freely  soluble 
in  alcohol. 

Identification  of  Benzoic  Acid. — After  neutralizing,  Fe2Clc  gives  a 
flesh-colored  or  reddish  ppt. 

Salicylic  or  oxybenzoic  acid,  HC7H503(C6H4.OH.COOH), 
is  present  in  oil  of  wintergreen  and  coal-tar. 

Experiment. — To  some  oil  of  wintergreen  add  five  times  as  much 
liquor  potassae,  and  heat  until  completely  saponified.  Now  add  HC1 
and  note  ppt.  of  crystals  of  salicylic  acid. 

It  is  usually  prepared  synthetically  by  treating  phenol  with 
NaHO,  and  then  the  resulting  NaC6H50  with  C02;  then  heat- 
ing without  air  to  convert  isomeric  NaC6H5C03  into  NaC7H503; 
and  finally  treating  with  HC1  to  liberate  the  acid.  Salicylic 
acid  appears  in  fine  needles  of  a  sweet  taste,  sternutatory,  and 
of  acid  reaction,  soluble  in  2.5  alcohol  or  450  H20. 

Identification. — Salicylic  acid,  even  in  very  dilute  solutions,  gives 
a  violet  color  with  ferric  salts. 

Cinnamic  acid,  C6H5.CHCH.COOH,  occurs  in  storax  and 
balsams  of  Peru  and  Tolu,  to  which  it  imparts  the  fragrant 
odor. 

Official  or  gallotannic  acid,  HC14H909,  obtained  by  extract- 
ing nut-galls  with  ether  and  alcohol  and  evaporating  solution, 
is  a  light-yellow,  scaly  compound;  bitter,  slightly  acid,  and 
strongly  astringent;  readily  soluble  in  water  and  dilute  alcohol. 
There  are  quite  a  number  of  closely  related  tannins  (oak-bark, 
nut-galls,  coffee,  tea,  etc.).  These  all  ppt.  albumin  and  gelatin, 
tartar  emetic,  and  most  alkaloids,  and  form  non-putrefying 
combinations  with  animal  compounds,  on  which  fact  the  process 


218  THE  CARBON  COMPOUNDS. 

of  tanning  depends.  They  produce  black  or  blue-black  ink  with 
Fe  salts,  and  hence  are  incompatible  with  these.  A  few  vege- 
table bitters  —  namely:  columbo,  quassia,  chiretta,  and  gentian 
—  contain  no  tannin  and  may  be  prescribed  with  Fe  solutions. 

Experiment.  —  Note  color  of  ppt.  formed  by  solutions  of  tannic  acid 
and  lime-water;  tannin  and  Fe2Cl6;  tannin  and  KHO. 

Gallic  acid,   HC7H505    [C6H2(OH)3.COOH],  is  made  by 
fermenting  nut-galls  or  tannin:  — 


It  occurs  in  long  needles,  more  soluble  in  alcohol  than  in  water, 
and  gives  a  blue-black  ppt.  with  ferric  salts,  but  does  not 
coagulate  albumin  or  ppt.  gelatin  or  alkaloids.  It  is  preferred 
to  tannin  for  internal  administration,  since  the  latter  must  first 
be  hydrolyzed  into  gallic  acid  before  it  can  be  absorbed. 

Experiment.  —  Add  a  fragment  of  KCN  to  solution  of  gallic  acid, 
and  notice  deep-rosy  color. 

Phthalic  acid  [C6H4(COOH)2]  is  a  dibasic  acid  used  as  a 
source  of  the  indicator  phenol-phthalein. 

The  relations  of  the  various  series  of  organic  acids  are 
shown  by  the  following  general  formulas:  — 


Acetic: 

Hydroxacetic,  or  lactic:    CnH2nOHCOOH. 
Dihydroxacetic,  or  glyoxylic:   CnH2n_1(OH)2COOH. 
Succinic:   CJE^(OOOH),. 

Hydroxysuccinic,  or  malic:  CnH2n_1OH(COOH)2. 
Dihydroxysuccinic,  or  tartaric: 
Citric  acid  is  expressed:     C3H4OH(COOH)3;    that  is,  hydroxy-pro- 
pane-tricarboxylic  acid. 

Hydrocyanic,  or  prussic,  acid,  HCN,  is  a  colorless  liquid 
with  an  odor  like  that  of  peach-blossoms;  it  changes  to  a  gas 
at  26.5°.  It  is  produced  spontaneously  by  decomposition  of 
amygdalin,  a  substance  present  in  bitter  cassava,  cherry-laurel, 
wild  cherry,  bitter  almonds,  and  the  pits  of  stone-fruit.  The 
United  States  Pharmacopeia  preparation  is  a  2-per-cent.  aque- 
ous solution  of  the  acid;  the  dose  of  this  preparation  is  from 
1  to  5  m.  It  is  slightly  acid,  but  very  poisonous.  AgN03  gives 
a  white  ppt.  of  AgCN,  not  darkening  in  the  light.  When  AgCN 
is  heated,  cyanogen,  ON,  is  liberated.  It  burns  with  a  flame 
the  color  of  peach-blossoms. 


FATS  AND  FIXED  OILS.  219 


FATS  AND  FIXED  OILS. 

These  are  esters  of  glyceryl  and  the  higher  fatty  acids,  and 
are  often  termed  glycerids.  They  are,  for  the  most  part,  mixt- 
ures of  triolein  [C3H5(C18H3302)3],  tripalmitin  [C3H5(C16H31- 
02)3],  and  tristearin  [C,HB(C18H8502)8].  The  first  is  a  liquid 
and  the  chief  constituent  of  oils;  the  second,  semisolid;  the 
third,  a  hard  solid.  In  plants  they  are  found  chiefly  in  seeds 
and  nuts;  in  animals  under  the  skin  and  upon  the  viscera  and 
muscles.  Human  fat  is  67  to  80  per  cent,  olein.  They  are 
usually  obtained  by  expression  or  melting.  So-called  margarin 
is  a  mixture  of  palmitin  and  stearin. 

Pure  fats  are  colorless,  odorless,  and  tasteless.  They  leave 
a  permanent  translucent  stain  on  paper.  They  differ  from 
mineral  oils  in  containing  0,  the  proportion  of  which  is  low  as 
compared  with  C.  They  are  insoluble  in  water  and  nearly  so 
in  cold  alcohol  (except  castor-oil  and  croton-oil),  but  are  readily 
dissolved  by  ether,  chloroform,  gasolin,  benzin,  benzene,  CS2, 
etc.  Fats  and  oils  are  emulsified  by  soap,  acacia,  or  albumins. 
Solid  fats  melt  below  100°  and  can  be  distilled  without  chemic 
change  at  about  300°,  but  are  decomposed  at  higher  tempera- 
tures into  a  number  of  products,  of  which  the  offensive  smell- 
ing aldehyd  acrolein,  C3H40  (from  glycerin),  is  most  distinctive. 
Ordinary  fats,  containing  albuminous  matter,  tend  to  become 
yellow  and  rancid,  after  a  time,  by  liberation  of  fatty  acids. 
Drying  or  siccative  oils  (linseed,  for  example)  are  so  called  be- 
cause they  contain  unsaturated  acids,  and  harden  by  taking  up 
0.  Albuminous  impurities,  which  prevent  this  oxidation,  are 
removed  by  treating  with  4  per  cent,  of  H2S04  and  decanting 
the  refined  oil.  Fats  and  oils  burn  readily,  giving  off  a  large 
amount  of  heat.  When  fats  or  oils  are  treated  with  alkaline 
hydroxids,  glycerin  is  set  free  and  a  soap  is  formed,  the  process 
being  termed  saponification.  When  treated  with  ferments  or 
superheated  steam  or  boiling  acidulated  water,  hydration  takes 
place  with  formation  of  glycerin  and  a  fatty  acid.  Fats  and  oils 
are  used  as  foods  and  medicines  and  in  paints  and  varnishes. 

The  purest  olive-oil  has  a  greenish  tinge.  On  cooling  to 
near  f.p.  it  separates  into  crystalline  palmitin  and  fluid  olein. 
Cotton-seed  oil  is  pale  yellow,  and  is  used  largely  as  an  adul- 
terant and  substitute  for  olive-oil,  butter,  and  lard,  as  are  also 
pea-nut  (earth-nut,  arachis)  and  sesame  (teel,  benne)  oils.  Oil 
of  almond  is  usually  straw-colored  and  should  have  no  odor  of 
bitter  almonds.  Codliver-oil  is  quite  complex.  In  addition  to 
the  fats,  jecolein,  palmitin,  stearin,  myristin,  and  therapin,  it 
contains  a  little  cholesterin  and  gaduic  acid,  gadium,  the  alka- 


220  THE  CARBON  COMPOUNDS. 

loids  asselin  and  morrhuin,  traces  of  I  and  Br,  and  various 
amins.  It  saponifies  very  readily,  and  hence  is  easy  of  diges- 
tion. The  inferior  grades  are  dark  in  color. 

Linseed-  or  flaxseed-  oil  is  about  80  per  cent,  linolein 
[C3H5(C18H3102)3].  Being  unsaturated,  it  absorbs  0  and  be- 
comes gummy.  The  same  glycerid  is  present  in  walnut,  hemp- 
seed,  sunflower,  poppy-seed,  and  niger-seed  oils.  The  drying 
effect  is  much  increased  by  boiling  the  raw  oil  in  a  current  of 
air,  sometimes  adding  oxid  of  Pb,  Fe,  or  Mn,  or  borates.  Lin- 
seed-oil is  used  in  paints  and  printers'  ink.  The  latter  is  a 
boiled  linseed  varnish  containing  lamp-black  or  some  other 
color  and  a  little  soap.  Drying  oils  may,  by  absorbing  0,  cause 
sufficient  heat  to  ignite  rags  or  clothing  soaked  therewith. 


Fig.  31.— Lard,  Crystallized  from  Chloroform. 

Castor-beans  are  nearly  one-half  oleum  ricini,  which  is 
noted  for  its  viscosity  and  nauseous  taste.  Besides  the  three 
usual  glycerids,  it  contains  ricinolein  [C3H5(C18H3302)3] ;  an 
alkaloid,  ricinin;  and  an  albumose,  ricin.  Five-per-cent.  castor- 
oil  in  petrolatum  increases  its  absorptive  power  for  H20  four- 
fold (10  parts).  Croton-oil  contains  a  peculiar  principle,  cro- 
tonol,  which  excites  a  pustular  eruption  when  applied  to  the 
skin.  Croton-oil  is  a  very  energetic  drastic  cathartic. 

Lard-oil  is  "cold  pressed":  that  is,  extracted  from  lard  at 
a  low  temperature.  It  is  used  in  cooking.  Benzoinated  lard 
contains  2  per  cent,  benzoin,  which  retards  rancidity. 

Experiment. — Dissolve  some  lard  in  warm  alcohol.  Examine  with 
microscope  the  crystals  that  form  on  cooling. 


FATS  AND  FIXED  OILS. 


221 


Butter  contains,  in  addition  to  92  per  cent,  of  olein,  pal- 
mitin,  stearin,  myristin,  and  arachidin,  the  glycerids  of  butyric 
(7  per  cent.),  capric,  caprcic,  and  caprylic  acids,  which  charac- 
teristic acids  are  volatile  and  soluble  in  water:  a  fact  that  is 
made  use  of  in  testing  butter  for  adulteration.  Butter  contains, 
as  a  rule,  15  to  20  per  cent,  of  water.  The  presence  of  butter- 
milk causes  butter  to  decompose  very  rapidly. 

Test  for  Butter. — Put  a  little  in  a  test-tube  and  add  two  or  three 
times  as  much  alcoholic  potash  solution,  and  warm  in  the  steam-  or 
water-  bath.  Now  add  a  few  drops  of  H2SO4,  and  notice  pine-apple  odor 
of  butyric  ether. 

Oleomargarin  is  a  butter  substitute  prepared  from  the  fat 
of  omentum  and  mesentery  of  beef-cattle.  This  fat  is  hashed 


Fig.  32.— Human  Fat,  Crystallized  from  Chloroform. 

fine  and  then  melted  at  about  50°.  The  liquid  fat  thus  pro- 
cured is  kept  in  small  vats  at  27°  for  two  or  three  days,  to 
allow  crystallization  of  the  harder  fats.  From  these  yellow 
oleo-oil  is  obtained  by  pressure,  and  is  churned  with  milk,  col- 
ored, and  rapidly  chilled.  Butterine  has  lard  added  to  oleo- 
oil  and  milk  before  churning. 

Palm-oil  is  brown  or  reddish  yellow  and  is  between  lard 
and  tallow  in  consistence.  Cacao-butter  (oleum  theobromatis) 
is  a  light-yellow,  brittle  solid  with  a  pleasant  odor,  melting  a 
few  degrees  below  the  temperature  of  the  body.  It  is  used 
extensively  as  a  basis  for  suppositories.  A  drop  of  glycerin 
added  to  each  suppository  (cold  process)  renders  it  more  cohe- 
sive. 


222  THE  CARBON  COMPOUNDS. 

The  elaidin  test  for  oils  consists  in  shaking  with  nitrous 
acid,  when,  if  positive,  white,  solid  elaidins  are  formed.  Olive-, 
almond-,  ben-,  mustard-,  rape-seed,  earth-nut,  bone-,  lard-, 
neat's-foot,  tallow-,  sperm-,  doegling-,  and  dolphin-  oils  all 
react  to  this  test. 

Lanolin,  or  wool-fat,  is  an  ester  of  the  cholesterins,  C26- 
H43HO.  It  is  light  yellow  in  color  and  has  the  odor  of  sheep's 
wool.  It  differs  from  ordinary  fats  in  being  miscible  with  twice 
its  weight  of  H20,  and  it  is  also  quite  a  stable  product.  The 
official  hydrous  lanolin  contains  not  more  than  30  per  cent,  of 
H20.  Lanolin  is  very  similar  to  human  sebum.  It  is  especially 
good  for  incorporating  liquids  in  ointments.  Any  stickiness  is 
overcome  by  adding  a  small  proportion  of  liquid  petrolatum. 

Lecithins,  or  phosphorized  fats,  are  found  in  nearly  all 
cells,  being  most  abundant  in  the  brain  and  nerves,  white  blood- 
corpuscles  and  yelk  of  eggs  (25  per  cent,  of  vitellin).  The  one 
most  frequent  in  the  animal  body  has  the  empiric  formula 
C44H90NP09.  Lecithin  is  soft  and  waxy,  forming  with  H20  a 
pasty  mass,  which  under  the  microscope  exhibits  the  "myelin" 
oily  drops  and  threads.  On  decomposition  lecithin  yields 
H3P04,  some  fatty  acid  (oleic,  palmitic,  or  stearic),  and  an 
organic  base,  cholin. 

SOAPS. 

Soaps  are  fatty-acid  salts  of  various  metals,  generally  ob- 
tained by  boiling  an  hydroxid  or  oxid  with  a  fat  or  oil:  lard, 
tallow,  olive,  cotton-seed,  palm,  pea-nut,  etc.  Soft  soap  is  a 
K  compound;  hard  soap  contains  Na.  The  oil,  the  fatty  acid, 
or  the  alkali  may  be  in  excess. 

Experiment. — To  10  c.c.  of  olive-oil  add  one-fifth  as  much  10-per- 
cent. KHO.  Boil  and  stir  until  mixture  is  homogeneous  and  no  oil 
separates  when  a  little  is  poured  into  water,  keeping  up  original  volume 
by  adding  H2O.  The  resulting  soft  soap  is  converted  into  hard  soap  by 
adding  saturated  solution  of  NaCl  and  allowing  to  cool. 

C3H5(C18H3302)3  +  3KHO  =  3KC18H33O2  +  C«HB(HO)8 
KC18H3302  +  NaCl  =  NaC18H3302  +  KC1 

K,  Na,  and  NH4  soaps  are  soluble  in  H20  and  alcohol,  but 
are  thrown  down  by  saturating  with  a  neutral  salt,  as  shown 
by  the  curd  formed  on  adding  common  salt;  all  others  are  in- 
soluble. Soaps  are  decomposed  by  mineral  acids,  which  set  free 
fatty  acids,  forming  new  salts.  Transparent  toilet  soaps  are 
made  with  castor-oil.  Lard  soaps  are  white  and  hard  and  often 
float  on  water.  Glycerin  is  present  in  all  soaps  made  by  re- 
action between  fats  and  alkalies;  it  is  absent  from  soaps  made 


FATS  AND  FIXED  OILS. 


223 


with  free  fatty  acids  liberated  by  superheated  steam.  The  com- 
mon yellow  soap  is  prepared  with  tallow-  or  palm-  oil  and  soda, 
and  often  also  some  rosin.  Palm  and  cocoa-nut  soaps  dissolve 
in  salt-water,  and  are  much  used  at  sea.  Cocoa-nut  oil  is  often 
added  to  a  soap  to  make  a  good  lather.  Various  coloring, 
odorous,  medicinal,  and  polishing  agents  (sand,  emery)  are  fre- 
quently added  to  soaps  for  special  purposes.  All  soaps  contain 
H20  (from  20  to  80  per  cent.),  with  which  the  smoothness 
varies.  Soaps  cleanse  by  union  in  excess  of  H20  of  their  freed 
alkali  with  the  greasy  dirt  on  the  surface  of  the  skin,  the  in- 
soluble salt  forming  a  slippery  lather.  When  used  in  hard 


Fig.  33.— Soap  Coppers. 


waters  insoluble  Ca  and  Mg  soaps  are  first  pptd.  before  there 
is  any  detergent  action  on  the  skin.  Soap-suds  are  due  to 
reaction  between  the  alkali  and  the  acid  salt  formed  by  the 
soap  decomposing  on  dissolving. 

The  official  soap  is  white  Castile,  a  Na  soap  made  from 
olive-oil.  The  mottled  appearance  of  some  Castile  soaps  is  due 
to  FeS04.  Ammonia  liniment  and  lime  liniment  are  fluid  soaps 
prepared  by  mixing  cotton-seed-  oil  with  NH4HO  (also  5-per- 
cent, alcohol)  and  linseed-oil  with  lime-water.  Green  soap 
(sapo  viridis)  is  usually  brown  in  color.  It  is  a  jelly-like  potash 
soap  made  by  adding  indigo  to  ordinary  soft  soap.  Lead  plaster 
is  chiefly  lead  oleate,  and  is  prepared  by  boiling  PbO  with  twice 


224:  THE  CARBON  COMPOUNDS. 

as  much  olive-oil  and  one-third  as  much  H20  for  several  hours. 
It  is  a  pliable,  tenacious  mass,  insoluble  in  water.  It  is  the 
basis  of  a  number  of  official  plasters.  Ungt.  diachylon  has  60 
parts  of  lead  plaster,  39  of  olive-oil,  and  1  part  of  oil  of  lav- 
ender. In  fusing  for  ointments  and  plasters  the  body  having 
the  highest  m.p.  should  be  melted  first,  then  the  others  in  order, 
stirring  in  any  insoluble  powder,  while  cooling. 


CARBOHYDRATES. 

Carbohydrates  are  compounds  of  C,  H,  and  0,  the  two 
latter  elements  in  the  same  proportion  as  in  water,  the  C  gen- 
erally in  6's  or  some  multiple  thereof.  They  are  derived  by 
oxidation  of  hexatomic  alcohols,  and  are  in  composition  mostly 
penta-oxyaldehyds  [COH.(CHOH)4.CH2OH  —  dextrose]  and 
penta-oxyketones  [CH2OH.(HCOH)3.CO.CH2OH  =  levulose], 
or  anhydrids  of  these.  Some  unimportant  carbohydrates  con- 
tain from  3  to  9  atoms  of  C. 

Carbohydrates  make  up  the  greater  bulk  of  plant-tissues; 
much  less  abundant  in  animals.  With  the  aid  of  sunlight  and 
chlorophyl  plants  build  up  formaldehyd,  then  sugar,  then 
starch,  cellulose,  and  proteins  from  the  waste-products  of  ani- 
mals. The  mineral  salts  are  similar  in  both  plants  and  animals. 
The  following  equations  represent  a  few  synthetic  results,  with- 
out representing  the  complex  intermediate  steps: — 

A  hydrocarbon:   10C02  +  8H2O  —  C10H]6  +  28O. 

A  carbohydrate:  6CO2  +  6H2O  =  C6H12O6  +  120. 

An  organic  acid:  2C02  +  H20  =  H2C2O4  +  0. 

A  nitrogenous  compound :   10C02  +  4H20  +  2NH3  =  C10H14N2  +  24O. 

Carbohydrates  are  mostly  white  and  solid.  All  have  a 
neutral  reaction.  They  are  generally  soluble  in  H20,  difficultly 
soluble  in  absolute  alcohol,  and  insoluble  in  ether.  Some  are 
crystalline;  others,  more  complex,  are  colloid.  They  sometimes 
form  loose  chemic  combinations  with  bases.  Unchanged  or 
after  treatment,  they  have  a  sweet  taste,  a  reducing  action  on 
certain  metals  (Cu,  Bi,  etc.),  and  power  to  rotate  polarized  light 
and  undergo  alcoholic  fermentation.  They  are  readily  oxidized 
in  alkaline  solutions,  turning  yellow  or  dark  brown  on  heating. 

According  to  their  structure,  carbohydrates  are  divided 
into  three  classes,  the  members  of  any  one  of  which  may  be 
converted  into  those  of  another  class  by  hydrolysis  or  dehydra- 
tion : — 


CARBOHYDRATES. 


225 


Polysaccharids     (amy- 
loses  or  amyloids) 


Cellulose  (cellulin). 

Lignin. 

Tunicin  (animal  cellulose — ascidians  and  cyn- 

thians). 
Starch  (amylum  or  glucosin-). 


(C6H10O5)n (6 to 200).  Mostly   I   Dextrins  (British  gum). 


colloid. 


Disaccharids  ( bioses  or 
saccharoses)  :  C12H22O17. 
Crystalline  and  dif- 
fusible. 


Inulin  (levulin — rotates  ray  to  left). 
G lycogen  ( liver-starch ) . 
Raffinose  and  lactosin  (crystalloid). 
Gums. 

Sucrose   (cane,  beet,  sorghum,  maple,    palm, 

sweet  fruits). 

Lactose  (milk-sugar,  C12H22On.H2O). 
Maltose  (malt-sugar). 
Isomaltose  (sweet  extracts,  amorphous). 

f  Dextrose  (grape-sugar,  glucose). 

j   Levulose  (fructose,  formose,  diabetin). 


simple  sugars):  C6H12O6. 
Crystalloid. 


In(teluscle.sngar  .  also  derived  from  hex- 
amethylene,  C6HI2). 


General  Test.  Molisch's  Reaction. — To  a  few  c.c.  of  dilute  syrup 
add  a  few  drops  of  15-per-cent.  alcoholic  solution  of  a-naphtol,  and  then 
add  very  slowly  twice  as  much  by  volume  of  H2SO4  as  of  the  sugar  solu- 
tion, sliding  it  down  the  side  of  the  inclined  tube.  Note  reddish-violet 
ring  of  furfurol. 

Cellulose,  or  plant-fiber,  forms  the  cell-walls,  or  frame- 
work, of  plants,  and  is  the  pulp,  or  indigestible  part,  of  fruit. 
The  trunks  of  trees  contain  also  6  or  7  per  cent,  of  mineral 
matter.  Pure  cellulose  is  prepared  by  grating  vegetable  tissue 
(flax,,  cotton,  hemp,  wood,  pith)  and  washing  away  the  starch. 
Absorbent  cotton  and  filter-paper  are  nearly  pure  cellulose.  It 
is  soluble  in  ammoniated  CuS04  (from  which  it  is  pptd.  as  a 
white  mass  by  acids)  and  in  strong  mineral  acids,  which  con- 
vert it  into  dextrin.  The  fine,  flexible,  elastic  fibers  of  cellulose 
are  pressed  or  woven  into  linen,  muslin,  thread,  ropes,  paper 
(wood-pulp  heated  with  CaS03  under  pressure),  and  papier- 
mache.  When  treated  with  H2S04,  cellulose  is  partly  changed 
into  a  jelly-like  glaze  of  hydrocellulose,  or  amyloid.  Unsized 
paper  dipped  first  into  H2S04  (4  volumes  to  1  of  H20),  and 
then  immediately  washed  and  dried,  is  converted  into  smooth, 
tough  parchment-paper. 

Experiment. — Prepare  parchment-paper  in  the  manner  mentioned, 
and  show  that  it  yields  blue  amyloid  reaction  with  H2SO4  and  I. 


226  THE  CARBON  COMPOUNDS. 

The  nitrocelluloses  are  important  explosive  and  combus- 
tible compounds  prepared  by  treating  cotton  or  paper  with 
HN03  and  H2S04.  Gun-cotton  is  the  trinitrate  [C6H702- 
(N03)3].  Pyroxylin  is  the  dinitrate  [C6H808(N08)2].  The 
styptic  fluid  collodion  is  a  solution  of  trinitrate  and  tetranitrate 
in  alcohol  and  ether.  Wood-silk  is  a  mixture  of  cellulose  and 
nitrocellulose.  Celluloid  is  a  smooth  material  prepared  by  in- 
corporating pyroxylin  with  camphor  and  sometimes  ZnO  or 
vermilion.  Xylonite  is  a  similar  pyroxylin  compound.  Smoke- 
less gunpowder  is  gun-cotton  gelatinized  with  acetone  or  acetic 
ether  and  then  dried  and  granulated;  or  gun-cotton  mixed  with 
nitrate  of  K  and  Ba;  or  gun-cotton  combined  with  nitroglyc- 
erin;  or  picric  acid;  or  nitronaphthalens.  On  destructive  dis- 
tillation cellulose  yields  CH3HO,  creasote,  C2H402,  etc.  Lignin 
is  very  similar  to  cellulose,  and  forms  the  inner  lining  of  woody 
cells  and  vessels. 

Starch  is  present  in  all  parts  of  plants,  especially  the  seeds, 
roots,  and  tubers,  where  it  serves  as  a  food-supply  for  the  young 
plant.  Rice  contains  77  per  cent,  of  starch;  potatoes,  21;  sago, 
90;  cereals,  50  to  70  per  cent.  It  occurs  in  small  grains  in  the 
cellulose  cells,  each  kind  having  a  different  microscopic  appear- 
ance according  to  its  origin,  0.002  to  0.020  in  diameter,  and 
concentric  arrangement  around  nucleus.  The  starch  is  sepa- 
rated by  grating,  washing,  and  decanting.  It  is  white,  taste- 
less, amorphous,  and  slippery  to  the  touch.  It  is  insoluble  in 
cold  water.  Hot  water,  alkalies,  or  ferments  loosen  the  outer 
insoluble  husk  (farinose)  and  set  free  soluble  granulose.  Acids, 
heat,  and  ferments  break  starch  down  into  dextrins,  then  iso- 
maltose,  maltose,  and  dextrose.  The  conversion  of  starch  into 
sugar  by  the  action  of  dilute  H2S04  is  an  hydrolytic  process, 
and  is  explained  by  the  fact  that  H2S04  diluted  with  H20  forms 
orthosulphuric  acid  (H2S04.2H20),  which,  with  the  aid  of  heat, 
gives  up  the  H20  to  the  starch  in  the  nascent  state,  as  it  were. 

Starches  are  much  used  as  food,  in  the  manufacture  of 
alcohol  and  glucose,  and  for  stiffening  paper  and  linen. 

Experiment. — Change  starch  to  sugar  by  boiling  with  a  little  H2O 
and  a  drop  of  H2SO4.  Note  change  in  taste. 

Test  for  Starch. — I  gives  a  purple  color  to  wet  starch;  brown,  to 
dry.  This  color,  due  to  C6H9IO5I,  disappears  on  heating,  and  is  partly 
restored  on  cooling.  The  color  is  likewise  destroyed  by  adding  anything 
which  will  form  a  compound  with  I,  as  Ag  salts,  alkaline  hydrates,  and 
sodium  thiosulphate. 

Dextrin  is  intermediate  between  starch  and  glucose  or 
maltose.  It  is  a  light-yellow,  amorphous  powder,  quite  soluble 
in  H20,  less  so  in  alcohol.  It  rotates  a  ray  of  polarized  light 


PLATE  I. 


r*3     Y'.JA     ***--•  fcrjpJL  C$tJ 


STARCHES.      (From  Bartley's  "Medical  and  Pharmaceutical  Chemistry.") 
i.    Potato  Starch.        2.     Bermuda  Arrowroot.        3.    Tous  les  Mois.        4.     St.  Vincent  Arrowroot. 
5.    Sago  of  Commerce.      6.    Port  Natal  Arrowroot.     7.    Rio  Arrowroot.     8.    Tapioca.     9.    Maize. 


CARBOHYDRATES.  227 

to  the  right.  Amylodextrin  (C30H50025)  gives  a  blue  color  with 
I;  erythrodextrin,  a  reddish-brown  color;  achrob'dextrin  and 
maltodextrin  give  no  color,  but  reduce  Cu  solutions  slightly. 
Dextrin  is  manufactured  on  a  large  scale  by  heating  starch  for 
a  short  time  at  160°  to  250°.  Dextrins  are  used  as  toast,  bread- 
crust,  infant-foods,  mucilage,  and  book-binders'  paste,  and  in 
dyeing,  calico-printing,  postage  stamps,  finishing,  and  glazing  of 
cards  and  wall-paper. 

Glycogen,  or  liver-dextrin,  imparts  a  sweet  taste  to  this 
organ,  the  carbohydrate  reservoir,  and  is  present  largely  in  mus- 
cular tissues  and  oysters.  It  is  a  white,  amorphous  powder, 
pptd.  by  alcohol  and  given  a  port-wine  color  by  I.  It  is  non- 
dialyzable. 

Gums  are  amorphous,  odorless,  tasteless,  viscid,  translucent 
substances  obtained  as  vegetable  exudations,  or  extracted  by 
alkalies  and  pptd.  by  HC1  and  alcohol.  Gum  arabic,  or  acacia, 
is  the  chief  Ca  salt  of  arabic  acid,  C12H22011;  it  is  acid  in  re- 
action, and  is  the  leading  emulsifier  in  pharmacy.  Other  com- 
mon gums  are  carrhageen  (Irish  moss),  lichenin  (Iceland  moss), 
bassorin  (tragacanth),  cerasin  (cherry-tree  gum),  marshmallow, 
flaxseed,  and  Senegal.  They  form  sticky  mucilages  with  H20. 
Heating  with  HC1  changes  them  to  dextrose  in  part.  They 
yield  mucic  acid  when  oxidized  by  HN03.  Pectin,  or  vegetable 
jelly,  constitutes  the  greater  portion  of  Irish  and  Ceylon  moss, 
and  is  the  substance  that  causes  vegetable  juices  to  gelatinize. 
Gums  are  used  in  medicine  as  demulcents. 

Sucrose  is  obtained  chiefly  from  cane  and  beets  by  crush- 
ing, then  coagulating  vegetable  albumin  by  boiling  with  1-per- 
cent, milk  of  lime,  treating  with  C02,  skimming,  boiling  with 
animal  charcoal,  filtering,  and  crystallizing  in  vacuum  appa- 
ratus, the  crystals  being  separated  by  centrifugation.  The  sugar 
remaining  in  molasses  can  be  extracted  by  adding  Sr(HO)2  and 
passing  in  C02  to  ppt.  SrC03.  Saccharose  is  sweet,  and  appears 
in  large  monoclinic  crystals;  sp.  gr.,  1.6;  very  soluble  in  H20 
(0.5  cold);  insoluble  in  strong  alcohol,  ether,  or  chloroform. 
It  is  inverted — i.e.,  converted  into  dextrose  and  levulose — by 
boiling,  acids,  or  ferment  action;  even  strongly  acid  fruit-juices 
have  power  to  invert  sucrose. 

+  66.5°  +52.5°         -94.4° 

C12H2Ai  +  H20  =  C6H1206  +  C6H1206 

Cane-sugar  melts  at  160°  and  cools  into  clear,  glassy 
barley-sugar.  At  higher  temperatures  it  turns  yellow,  forming 
dextrose  and  a  gummy  substance  called  levulosan.  On  heating 


228 


THE  CARBON  COMPOUNDS. 


still  further  (200°)  it  gives  off  gases  and  darkens  into  brown 
caramel  from  loss  of  H20,  being  finally  reduced  to  one-third  its 
volume  of  coke.  H2S04  also  chars  cane-,  but  not  grape-  or 
milk-  sugar.  Cane-sugar  does  not  undergo  alcoholic  fermenta- 


Fig.  34.— Vacuum  Pan. 


tion,  except  indirectly  through  invertase,  and  does  not  respond 
to  the  copper  tests.  It  forms  insoluble  sucrates  or  saccharosates 
with  Ca,  Ba,  and  Sr  hydrates.  It  is  used  in  food,  syrups,  pre- 
serves, and  wines.  Caramel  is  employed  to  color  liquors,  vine- 
gars, confectionery,  etc. 


CARBOHYDRATES.  229 

Experiment. — Change  cane-sugar  to  glucose  by  dissolving  a  few 
grains  in  H2O,  adding  a  drop  of  H.,SO4,  and  boiling  ten  or  fifteen  minutes. 
Prove  that  this  product  reduces  alkaline  CuSO4  solution,  changing  the 
color  from  blue  to  yellow,  then  red,  whereas  cane-sugar  solution  has  no 
such  reducing  effect. 

Lactose  constitutes  3  to  7  per  cent,  of  milk,  and  is  a  by- 
product in  the  manufacture  of  cheese,  the  whey  being  evapo- 
rated and  the  sugar  collected  on  strings  and  sticks.  It  is 
slightly  sweet;  sp.  gr.,  1.5;  soluble  in  6  parts  of  water.  It 
undergoes  lactic  and  alcoholic  fermentation  (with  ordinary,  not 
pure,  yeast)  and  responds  to  the  glucose  reduction  tests.  Dilute 
acids  convert  it  into  galactose  and  dextrose.  Owing  to  its  hard- 
ness and  grittiness,  it  is  widely  utilized  in  powders  and  tablet 
triturates. 

Maltose  is  obtained  from  starch  by  diastatic  fermentation, 
or  by  boiling  with  dilute  H2S04.  The  same  change  takes  place 
spontaneously  during  the  germination  of  seeds.  It  appears  in 
white  needles  soluble  in  both  water  and  alcohol.  On  hydrol- 
ysis it  breaks  up  into  two  molecules  of  dextrose.  It  ferments 
with  yeast  to  alcohol  and  responds  to  the  glucose  reactions. 
Maltose  and  lactose  are  distinguished  from  glucose  by  not  re- 
ducing Barfoed's  reagent  (solution  of  cupric  acetate  in  acetic 
acid). 

Dextrose  makes  up  10  to  50  per  cent,  of  grape-juice,  and 
is  widely  distributed  in  vegetables  (raisins,  figs,  and  other  sweet 
fruits)  and  honey,  usually  with  an  equal  amount  of  levulose, 
the  mixture  being  known  as  invert-sugar.  It  is  the  form  in 
which  carbohydrates  are  absorbed  into  the  blood,  and  is  present 
in  diabetic  urine.  It  is  manufactured  on  a  large  scale  by  heat- 
ing starch  or  cellulose  with  dilute  acids,  excess  of  acid  being 
removed  with  chalk.  It  is  crystalline  (small  cubes  or  square 
plates)  if  anhydrous;  it  is  only  half  as  sweet  as  sucrose,  and 
soluble  in  its  own  weight  of  water  and  in  dilute  alcohol.  With 
yeast  it  ferments  to  alcohol  and  C02,  and  also  may  undergo 
lactic-acid  (in  presence  of  milk  or  cheese)  or  butyric-acid  fer- 
mentation. 

C6H1206  =  2C3H603       2C3H603  =  C4H802  +  2C02  +  2H2 

By  oxidation  it  is  changed  to  saccharic  or  oxalic  acid.  It  is  a 
strong  reducing  agent  (1  molecule  =  5CuO).  It  aids  the  solu- 
tion of  lime  in  water.  It  is  used  in  food  as  syrups  and  in  pre- 
serves, confectionery,  and  artificial  honey;  also  in  printers' 
rollers  and  copying  inks. 

Experiment.  —  Show  reducing  action  of  dextrose  on  an  alkaline 
aqueous  mixture  of  some  Bi  salt.  Note  the  change  from  white  to  gray  or 
black. 


#30  THE  CARBON  COMPOUNDS. 

Levulose  occurs  with  dextrose  as  invert-  or  fruit-  sugar. 
The  purest  is  obtained  from  inulin.  It  appears  as  needle-shaped 
crystals  or  a  thick  syrup,  which  prevents  dextrose  from  crystal- 
lizing. It  responds  to  the  dextrose  test  with  two-thirds  as  much 
reducing  power.  Both  dextrose  and  levulose  can  be  prepared 
synthetically  (acrose)  from  HCOH  by  treating  with  milk  of 
lime.  It  is  used  as  a  substitute  for  cane-sugar  in  diabetes. 

Galactose  is  obtained  from  lactose  or  gums  by  hydrolysis, 
and  is  present  in  koumiss  and  kefir.  It  does  not  ferment  with 
yeast,  but  reduces  Cu  solutions.  On  oxidation  it  is  changed 
into  mucic  acid. 

Many  unimportant  compounds  are  produced  by  the  oxi- 
dation of  hexatomic  alcohols.  Rhamnose  has  the  formula 
C6H1205;  glycerose,  C3H603;  erythrose,  C4H804;  mannose  (from 
mannite),  C6H1406.  Pentosanes  are  plant-products  yielding 
pentoses  by  hydration.  Inulin,  from  elecampane,  is  an  ex- 
ample; arabinose,  C5H1005,  is  another.  Scyllite  is  a  sugar  ob- 
tained from  fishes.  Bioses  and  trioses  are  composed  of  2  or  3 
molecules  of  glucose  with  H20.  On  heating  invert-sugar  with 
dilute  mineral  acids  it  yields  levulinic  acid,  C5H803,  and  humous 
substances. 

GLUCOSIDS,  OR  COMPOUND  SUGARS. 

The  glucosids  are  compound  ethers  which,  under  the  in- 
fluence of  ferments  or  dilute  acids  or  alkalies,  take  up  H20  and 
split  into  glucose  and  other  products.  They  are  generally  neu- 
tral, soluble  (except  in  ether),  and  crystalline.  Many  are  optic- 
ally active  (levorotatory).  Some  contain  N.  They  are  usually 
of  vegetable  origin  (often  accompanied  by  a  ferment)  and  are 
extracted  with  water  or  alcohol,  decolorized  with  animal  char- 
coal and  crystallized.  They  can  be  made  synthetically  from 
glucoses  dissolved  in  alcohol,  into  which  HC1  gas  is  passed. 
They  are  incompatible  with  free  acids,  alkalies,  or  ferments. 
Their  names  nearly  all  end  in  in  (Latin,  inum),  exceptionally 
in  etin,  egol,  or  idin.  Below  is  a  list  of  the  most  important 
glucosids: — 

Absinthin. — Bitter  principle  of  wormwood.  Absinthe  is 
sweetened  dilute  alcohol  flavored  with  oil  of  wormwood  and 
colored  with  chlorophyl. 

Adonidin. — Adonis  vernalis;   cardiac  tonic. 

Amygdalin  (C^H^NOn). —  White,  crystalline  powder; 
bitter  almond,  cherry-laurel,  etc.;  dilute  acids  convert  into 
dextrose,  benzoic  aldehyd,  and  HCN;  same  change  spontaneous 
in  aqueous  extracts,  owing  to  action  of  ferment  emulsin. 


GLUCOSIDS.  231 

Arbutin. — Uva  ursi;   bitter. 

Baptisin. — Baptisia  tinctoria;   purgative. 

Bryonin. — Bryonia-root;  hydragog. 

Cathartic  Acid. — Senna. 

Cerebrin. — Brain-  and  nerve-  tissue;  yields  galactose  or 
cerebrose. 

Chitin. — Shells  of  crustacese. 

Colocynthin. — Colocynth-f ruit ;  purgative. 

Coloring  Principles. — See  "Indican,"  "Carminic"  and  "Ru- 
berythric  Acids,"  and  "Xanthorhamnin." 

Coniferin. — Woody  tissue  of  sugar-cane  and  cambial  juice 
of  conifers;  yields  vanillin  with  O03. 

Convallamarin. — Convallaria ;  heart-tonic. 

Convolvulin. — Jalap;   drastic  purgative. 

Cotoin. — Active  principle  of  coto. 

Digitalin  (C5H802). — White,  amorphous,  bitter  substance 
from  leaves  of  fox-glove;  soluble  in  1000  H20  or  100  dilute 
alcohol;  yellow  solution  with  HC1.  Other  digitalis  principles 
are  digitonin  (amorphous,  yellow,  soluble  in  alcohol),  digitoxin 
(colorless,  crystalline,  very  poisonous,  not  a  glucosid),  and 
digitalein  (white,  amorphous,  very  bitter).  Boiling  with  dilute 
acids  yields  resinous  substances. 

Identification  of  Digitalin. — Solution  in  H2S04  is  yellow,  gradually 
turning  blood-red,  or  changing  to  violet  on  adding  a  drop  of  HNO3  or 

Fe2Clc  solution. 

Esculm. — Bark  of  horse-chestnut. 

Fraxin. — Ash-bark. 

Gentiopicrin. — Gentian-root. 

Glycyrrhizin.  —  Licorice-root;  quinin  and  acids  incom- 
patible— form  resinoid  bitter  and  sugar,  like  glucose. 

Helleborin  and  Helleborein. — Black  and  green  hellebore. 

Jalapin. — In  jalap-resin;   soluble  in  ether. 

Leptandrin. — Leptandra,  or  Culver's  root. 

Myronic  Acid  (C10H19NS2010). —  In  black  mustard  as  K 
salt  (sinigrin);  this  salt  decomposed  by  ferment  myrosin  as 
follows: — 

KC10H18NS2010  =  C6H1206  +  C3H5NCS  (allyl  mustard  oil) 
+  KHS04. 

Mustard  plasters  are  rendered  inert  by  hot  water,  which  coagu- 
lates ferment  myrosin  and  prevents  formation  of  sulphocyanate, 
to  which  the  mustard  owes  its  virtue. 

Phloridzin. — Root-bark  of  apple,  pear,  plum,  and  cherry; 
causes  glycosuria. 


232  THE  CARBON  COMPOUNDS. 

Populin. — Bark  and  leaves  of  trembling-poplar;  with  ben- 
zoic  acid. 

Quercitrin. — Sumach,  and  grape-vine;  coloring  principle. 

Salicin  (C13H1807). — Willow-  bark  and  leaves;  combination 
of  C6H12Ce  and  oxybenzyl  alcohol,  C6H4OH.CH2OH;  white, 
crystalline,  soluble  in  28  H20  or  60  alcohol;  H2S04  turns  deep 
red. 

Santonin. — Wormseed;  shining,  colorless  prisms,  turned 
yellow  by  light;  sparingly  soluble  in  H20,  but  more  so  in  alco- 
hol and  ether. 

Identification  of  Santonin. — Heat  on  porcelain  and  add  H2S04  and 
an  equal  volume  of  very  dilute  Fe2Cl6.  A  red  color  is  developed,  turn- 
ing purple,  then  violet. 

Saponin. — Quillaia,  senega,  horse-chestnut,  etc.;  white, 
friable  powder;  frothy  foam,  like  soap. 

Scammonin. — Scammony-resin;   soluble  in  ether. 

Scillitin.— Squill-bulbs. 

Solanin. — Solanum  species  and  potato-sprouts;   poisonous. 

Sinalbin. — White  mustard. 

Strophanthin. — Seed  of  African  climbing  plant  used  for 
arrow-poison;  heart-tonic;  colored  dark  green  by  H2S04,  turn- 
ing red-brown. 

Tannin  (C14H1009).  —  Wide  distribution;  acid  reaction; 
soluble,  astringent,  bitter;  incompatible  with  nearly  every- 
thing; tea,  leather,  inks,  dyeing.  Styptic  collodion,  a  saturated 
solution  of  tannin,  is  a  valuable  styptic,  particularly  for  bleed- 
ing gums. 

Experiment. — Boil  1  gm.  of  tannin  for  fifteen  minutes  in  10  c.c.  of 
5-per-cent.  H2SO4;  then  neutralize  with  excess  of  marble-dust  and  test 
filtrate  for  glucose. 


VEGETABLE  COLOEING  MATTERS. 

Litmus. — A  lichen;   litmic  acid,  red;   salts,  blue. 

Curcumin. — Resin  of  turmeric  root;  yellow  color,  turned 
red-brown  by  alkalies;  soluble  in  CHC13  (saffron  and  mustard 
not);  used  to  color  mustard,  chow-chow,  and  vermicelli. 

Chlorophyl. — Eesinoid  mixture  of  xantho-  and  cyano-;  con- 
tains Fe;  necessary  to  life  and  growth  of  plants;  soluble  in  alco- 
hol and  ether,  but  not  in  water. 

Hematoxylin. — Logwood;  yellow  solid,  red  liquid;  dye  and 
section-stain. 

Carminic  Acid. — Coloring  constituent  of  cochineal  (dried 
female  insects  on  cactuses);  carmin  prepared  by  extracting 


COLORING  MATTERS.  233 

cochineal  with  H20  and  pptg.  with  alum  and  lime  —  reddish- 
purple  magma  soluble  in  water  and  alcohol  and  KH4HO.  Face- 
rouge  is  carmin  with  starch  or  French  chalk;  lac-dye  is  a  cheap 
form  of  cochineal. 

Indican.  —  In  woad  and  indigo  plant;  acids  change  to 
indigo-blue  and  indiglucin.  Indigo-blue  (C16H10N202),  insol- 
uble in  alcohol,  water,  or  ether;  soluble  in  H2S04  or  CHC13; 
reduced  to  indigo-white  (C16H12N202)  by  nascent  H;  has  been 
prepared  synthetically  from  toluene. 

Ruberythric,  or  Rubianic,  Acid.  —  A  glucosid  in  madder- 
root;  yields  by  fermentation  alizarin  (turkey-red)  and  purpurin. 

Xanthorhamnin.  —  Coloring  matter  of  buckthorn,  or  Rham- 
nus  tinctoria. 

Bixin  and  Orellin.  —  Red  and  yellow  scales,  fruit  of  B. 
orellana;  colors  yellow  (annatto  —  butter). 

Brasilin.  —  Brazil  wood;  amber  yellow;  fused  with  KHO 
yields  resorcin. 

Saffranin  (Polychroit).  —  Glucosid  in  saffron,  or  crocus; 
colors  food  yellow. 

Santalin.  —  Crystalline  resinoid  in  red  saunders  wood;  also 
barwood  and  camwood. 

Alizarin  (  orthodioxyanthraquinone) 


is  obtained  from  madder-root  (Rubia  tinctoria);  now  usually 
formed  by  synthesis  from  anthracene.  Fine  red  crystals,  readily 
soluble  in  alcohol  and  ether.  Turkey-red  dye;  violet  or  purple 
with  alkalies;  various  colored  lakes  with  metallic  oxids:  red 
with  Al  and  Sn,  violet-black  with  Fe,  reddish  blue  with  Ca. 
Naphthazarin,  or  alizarin  black,  is  dioxynaphthoquinone  [C10- 
H4(OH)202].  Alizarin  orange  is  obtained  by  the  action  of 
N204  on  alizarin;  alizarin  blue  by  heating  alizarin  orange  with 
glycerin  and  H2S04.  Alizarin  brown,  or  anthragallol,  is  an 
isomer  of  purpurin,  or  trioxyanthraquinone  [C14H5(OH)30,]. 

Triphenyl-methane  Coal-tar  Dye-colors.  —  Malachite-Green 
Group  of  Diamido  Derivatives.  —  Malachite  green  (colorless 
base):  — 

fC6H4N(CH3)2 
C6H4N(CH3)2 


Commercial  dyestuff:   chlorhydrate  or  ZnCl2  double  salt. 


234  THE  CARBON  COMPOUNDS. 

Rosanilin  Group. — Fuchsin,  or  magenta;  chlorhydrate  of 
rosanilin: — 

fC6H3CH3NH2 
C^C6H4NH2 
[  C6H4NH  HC1 

Methyl  violet,  or  pyoktanin  also. 

Eosolic-Acid  Group. — These  are  acid  dyes  of  no  present 
importance,  and  are  formed  from  anilin  bv  substitution  of  HO 
for  NH2. 

Phthalein  Group. — Produced  by  reaction  of  a  molecule  of 
phthalic  anhydrid  [C6H4(CO)20]  on  2  molecules  of  phenol, 
with  liberation  of  H20.  Phenol-phthalein  is  an  indicator  for 
alkalies;  fluorescein,  or  resorcin-phthalein,  is  used  as  the  Na 
salt  (uranin)  to  dye  wool  yellow;  eosin  is  the  K  salt  of  tetra- 
brom-fluorescein,  and  dyes  silks  and  woolens  reddish.  Noso- 
phen  (tetra-iodo-phenol-phthalein)  contains  60  per  cent,  of 
iodin.  It  is  yellow  and  insoluble,  but  forms  soluble  salts  with 
alkalies.  Eudoxin  is  a  red-brown,  insoluble  Bi  salt  of  nosophen. 


UNCLASSIFIED  BITTEK  PRINCIPLES. 

Aloins. — Yellow,  bitter,  minute  needles  from  Aloes  Barba- 
densis  or  Socotrina;  slightly  soluble  in  water,  but  more  so  in 
alcohol;  barb-,  soc-,  or  nat-  aloin. 

Identification  of  Aloin.  —  Dissolve  in  strong  H2SO4  and  a  little 
HNO3,  and  dilute  with  H20:  A  yellow  color  (blue,  nataloin;  no  color, 
socaloin),  turning  deep  claret  with  excess  of  NH4HO. 

Cantharidin. — Spanish-fly  blister. 

Cimicifuga. — Black  snakeroot. 

Cotoin. — Bolivian  coto. 

Cubebin. — Cubeb-berries. 

Elaterin. — Neutral  principle  deposited  by  juice  of  "squirt- 
ing cucumber";  most  powerful  hydragog  known. 

Euonymin. — Wahoo-bark. 

Phytolaccin. — Crystalline  substance  from  poke-  root  and 
fruit. 

Picrotoxin. — Crystalline  bitter  convulsant  from  Cocculus 
Indicus. 

Serpentaria. — Virginia  snakeroot. 

Quassin. — Quassia-bark;   simple  bitter. 


PHENOLS.  235 


PHENOLS. 

These  are  substitution  products  of  benzene,  in  which  one 
or  more  atoms  of  H  are  replaced  by  OH.  They  stand  between 
organic  acids  and  true  alcohols;  they  differ  from  alcohols  in 
not  oxidizing  to  aldehyds  and  acids,  but  they  form  ethers. 

Phenol  (phenic,  phenylic,  or  carbolic  acid),  C6H,.OH,  is 
manufactured  from  coal-tar  oil  distilled  at  150°  to  190°.  It 
appears  in  crystals  with  characteristic  aromatic  odor  and  sweet, 
burning,  and  numbing  taste.  It  fuses  at  35°  to  41°;  b.p.,  178°; 
and  is  liquefied  by  5  parts  and  soluble  in  20  of  H20  and  in 
nearly  every  other  solvent.  It  is  neutral  or  faintly  acid.  It 
coagulates  albumin  and  collodion.  Phenol  is  a  valuable  sur- 
gical antiseptic,  but  very  poisonous.  The  salts  of  phenic  acid 
are  termed  phenates  or  carbolates,  as  NaC6H50.  Phenol  crys- 
tals and  solutions  tend  to  turn  red. 

Identification  of  Phenol. — Fe2Cl6  gives  a  permanent  violet  color. 
Br  water  gives  white  ppt.  of  tribromphenol.  NH3,  or  Labarraque's  solu- 
tion, colors  blue. 

Cresol  (cresylic  acid),  C6H4.CH3.OH,  is  impure  carbolic 
acid  obtained  from  coal-tar  by  fractional  distillation.  Among 
its  derivatives  are  creolin,  lysol,  and  solveol. 

Creasote  is  a  mixture  of  phenols,  especially  guaiacol,  C6H4.- 
OH.OCH3,  and  creosol,  or  wood-tar,  C6H3.CH3.OH.OCH3,  ob- 
tained from  coal-tar.  It  is  a  yellow,  oily  liquid  with  smoky  odor 
and  burning  taste,  soluble  in  150  H20  and  freely  in  other 
solvents,  except  glycerin;  b.p.,  205°  to  215°;  miscible  with  an 
equal  volume  of  collodion.  It  is  used  chiefly  as  an  intestinal 
antiseptic. 

Identification  of  Creasote. — Fe2Cl6  gives  a  violet  color,  changing 
to  green  and  brown. 

Resorcin,  C6H4(OH)2,  appears  in  colorless  crystals  which 
have  a  sweet  taste  and  are  very  soluble.  It  is  formed  by  fusing 
resins  with  caustic  alkalies.  It  is  only  slightly  poisonous,  and 
is  used  as  a  gastro-intestinal  antiseptic  and  in  manufacturing 
dyes.  Fe2Cl6  gives  a  blue  or  violet  color  with  weak  solutions. 

Pyrocatechin  (catechol)  and  hydroquinone  are,  respect- 
ively, ortho-  and  para-  dihydroxy-benzene.  Guaiacol  is  mono- 
methyl  catechol;  its  carbonate  is  prepared  by  saturating  with 
XaHO  and  treating  with  COC12. 

Pyrogallin  [C6H3(OH)3]  appears  in  glistening,  white,  gen- 
erally soluble  needles,  prepared  by  heating  gallic  acid  to  200°, 
by  which  C02  is  driven  off.  It  is  a  good  reducing  agent,  and 


236  THE  CARBON  COMPOUNDS. 

is  used  as  a  developer  (deoxidizing  agent)  in  photography.    It 
turns  red  with  ferric,  blue  with  ferrous,  salts. 

Experiment. — Show  rapid  oxidation  (darkening)  of  pyrogallin  with 
alcoholic  solution  of  KHO  when  exposed  to  the  air.  For  the  same  reason 
it  furnishes  a  delicate  test  for  traces  of  HNO3. 

Phenol-phthalein,  C20H1404,  is  prepared  by  dehydrating 
phthalic  acid  by  heating  and  then  treating  the  anhydrid  with 
phenol  in  presence  of  H2S04,  which  removes  another  molecule 
of  H20.  It  is  a  valuable  indicator  in  alkalimetry. 

The  naphtols  (a.  and  I.),  C10H7OH,  are  similar  to  the 
phenols,  being  intestinal  antiseptics  derived  from  naphtalen. 
Betanaphtol  is  used  medicinally,  as  alphanaphtol  is  poisonous. 
It  appears  in  shining  plates  with  carbolic  odor  and  burning 
taste.  It  is  readily  soluble  except  in  H20  (1000  parts).  Aque- 
ous solutions  are  colored  green  by  Fe2Cle.  Sodium  naphtol 
(microcidin),  C10H7.0]Sra,  is  used  in  aqueous  solutions  as  a  dis- 
infectant for  cleansing  dental  instruments. 

NITEO-DERIVATIVES. 

Nitrobenzene  (mirbane  essence),  C6H5N02,  is  a  yellow,  oily 
compound,  formed  by  nitration  of  benzene.  It  has  the  odor  of 
bitter  almonds  and  is  used  to  flavor  confectionery  and  per- 
fumery. It  is  the  source  of  anilin  and  coal-tar  dyes. 

Picric  or  carbazotic  acid  (trinitrophenol),  C6H2(N02)3OH, 
is  prepared  by  acting  on  phenol,  silk,  or  wool  with  HN03.  It 
ppts.  alkaloids  and  albumin,  and  is  used  as  a  yellow  dye  and 
in  explosives  (lyddite). 

(See  also  "Ethers"  and  "Carbohydrates.") 

THIO-COMPOUNDS. 

Sulphocarbolic  acid,  HS03.C6H4OH  (phenol-sulphonic,  or 
sozolic,  acid),  is  formed  by  dissolving  phenol  in  strong  H2S04. 
Na  and  Zn  sulphocarbolates  are  wrhite  soluble  salts  used  as 
intestinal  antiseptics. 

Ichthyol  (Na  or  NH4,  ichthyo-sulphonate) ,  C26H36S:,Na20(5, 
is  a  brown,  tarry,  strong-smelling  liquid,  obtained  by  dry  dis- 
tillation of  a  bitumen  found  in  Tyrol. 

Mercaptans  (so  called  from  their  affinity  for  HgO),  or 
hydrosulphids,  are  alcohols  in  which  S  has  replaced  0.  They 
are  liquids,  insoluble  in  H20,  inflammable,  and  with  an  un- 
pleasant odor  like  leeks.  They  may  be  formed  by  treating 
haloid  ethers  with  KSH. 


THIO-COMPOUNDS.  237 

C2H5C1  +  KSH  =  KC1  +  C2H5SH  (ethyl  mercaptan) 

Combined  with  oxids  they  yield  mercaptids;  with  aldehyds, 
mercaptals;  with  ketones,  mercaptols.  The  oxidation  of  mer- 
captans  yields  sulphonic  acids;  of  mercaptols,  sulphonals.  The 
hypnotic,  sulphonal 

CH3  \  p  /  S02C2H5 

CH3  /  ^  \  S02C2H5 

(diethyl-sulphon-dimethyl-methane)  is  formed  by  the  reaction 
between  acetone,  ethyl  mercaptan,  and  K2Mn208.  It  is  a  color- 
less, tasteless,  odorless,  crystalline  substance,  soluble  in  hot 
water. 

Experiment. — Heat  a  mixture  of  sulphonal  and  wood  charcoal,  and 
note  characteristic  odor  of  mercaptans. 

Trional,  another  hypnotic,  is  diethyl-sulphon-methyl-ethyl- 
methane: — 

CH3\p/C2H5S02 
C2H5  /  V\  C2H5S02 

and  tetronal  is  diethyl-sulphon-diethyl-methane: — 

C2H5\r/C2H5S02 
C2H5  /  ^  \  C2H5S02 

These  are  soluble  in  boiling  water,  alcohol,  and  ether. 

Allyl  sulphid  ("garlic  oil"),  (C3H5)2S,  is  the  most  impor- 
tant thio-ether.  It  is  obtained  from  garlic-leaves  and  the  seeds 
of  many  cruciferse. 


AMIDO-PHENOLS. 

These  are  formed  by  reduction  of  the  corresponding  nitro- 
phenols.  The  ethyl  ethers  of  para-amido-phenol,  C6H4.OH.NH2, 
are  termed  phenetidins.  From  para-phenetidin,  C6H4.OC2H5.- 
NH2,  phenacetin  (acetparaphenetidin),  C6H4.OC2H5.NHC2H?0, 
is  formed  by  treating  with  glacial  acetic  acid.  It  is  a  crystalline 
substance,  soluble  in  alcohol,  and.  is  one  of  the  best  and  safest 
of  the  coal-tar  remedies.  Phenocoll,  or  glycocoll  phenetidin, 
has  the  formula  C6H4.OC2HvNH.COCH2NHa.  Methacetin,  or 
para-acetanisidin  =  C6H4.OCH3.NH.C2H30. 


238  THE  CARBON  COMPOUNDS. 


COMPOUND  AMMONIAS. 

Amins  are  alkyl  substitutes  of  NH3.  They  are  primary, 
secondary,  and  tertiary,  according  as  1,  2,  or  3  atoms  of  H  are 
replaced.  They  are  mon-,  di-,  or  tri-  when  1,  2,  or  3  molecules 
of  NH3  are  represented.  They  contain  no  0.  They  are  char- 
acterized by  a  strong,  disagreeable  odor,  often  like  dead  fish. 
With  HN02  primary  amins  yield  corresponding  alcohols.  Amins 
also  combine  with  acids  to  form  salts. 

The  three  methyl  monamins  [CH3NH2,  (CH3)2NH,  and 
(CH3)3N]  are  found  in  herring  brine  and  many  other  decom- 
posing products.  The  first  is  a  combustible  gas;  the  others, 
liquids. 

Diethylen-diamin  [(C2HJ2(NH)2~\,  or  piperazin,  appears 
in  rhombic  plates,  readily  soluble.  It  is  used  as  a  solvent  for 
uric  acid  and  gouty  concretions. 

Urotropin,  hexamethylen-tetramin,  is  a  crystalline  substance 
soluble  in  water,  used  as  a  genito-urinary  antiseptic. 

Saccharin  (anhydro-ortho-sulphamin-benzoic  acid),  C^H^- 
COS02NH,  is  a  coal-tar  product,  from  toluol,  280  times  as 
sweet  as  cane-sugar.  It  is  soluble  in  alcohol  and  ether,  and 
may  be  detected  by  this  fact. 

Found  in  the  cadaver  are  the  diamins  putrescin  and  cadav- 
erin.  Isoamylamin  is  a  very  poisonous  ptomain  sometimes 
present  in  decomposing  yeast  and  codliver-oil. 

Cacodyl,  or  diarsenic  tetramethyl  [As2(CH3)4])  is  a  color- 
less, very  poisonous  liquid  with  an  extremely  offensive  odor. 
It  takes  fire  on  exposure  to  air.  Cacodyl  oxid  [As2(CH3)40] 
is  formed  by  dry  distillation  of  a  mixture  of  As203  and  KC2- 
H302.  It  is  a  poisonous,  oily  liquid  which,  when  oxidized  with 
HgO,  yields  cacodylic  acid  [(CH3)2AsO.OH],  an  odorless,  crys- 
talline substance,  non-poisonous,  and  recently  used  in  medicine. 
Given  hypodermically  it  sets  up  symptoms  of  As  poisoning. 

Amids  consist  of  an  acid  radical  with  the  group  amidogen, 
NH2.  They  result  when  NH2  replaces  OH  in  acids.  They  con- 
tain C,  N,  0,  and  H.  Imids  have  the  group  NH  instead  of  KH2. 

Acetamid,  C2HSO.NH2,  is  prepared  simply  by  heating 
NH4C2H302,  driving  off  H20.  It  appears  in  soluble  crystals 
with  a  mousy  odor. 

Carbamid,  or  urea  [(NH2)2CO^,  was  about  the  first  or- 
ganic compound  prepared  synthetically,  by  heating  its  isomer: 
NH4CNO.  It  is  the  chief  solid  constituent  of  urine. 

Formamid,  NCHO.H2,  is  a  colorless  liquid  which  com- 
bines with  chloral  to  form  the  soluble  crystalline  hypnotic 
chloralamid: — 


COMPOUND  AMMONIAS.  239 

N.CHO.H2.C2HC130 

Phenylamin,  or  anilin,  NH2CQH5,  is  a  colorless,  oily  liquid, 
nearly  insoluble  in  H20.  It  is  prepared  by  treating  C0H6  with 
HN03  and  nascent  H  (Fe  and  HC1).  It  is  a  narcotic  poison, 
and  is  the  basis  of  the  anilin  dyes  (not  poisonous),  which  are 
made  by  oxidation  processes.  Bleaching  powder  and  anilin 
give  a  purple  dye;  K2Cr207,  H2S04,  and  anilin,  blue: — 

NH2C6H5  +  2C7H9N"  (toluidin)  +  30  =  C20H19N3  (rosan- 
ilin)  +  3H20. 

Experiment. — Make  rosanilin  hydrochlorate  by  warming  2  gm.  of 
HgCl2  and  3  or  4  drops  of  anilin  until  the  color  becomes  green  and  then 
purple.  Let  cool  and  add  a  few  drops  of  alcohol  and  a  drop  or  two  of 
HC1.  Then  stir  into  beaker  of  H20. 

Anilids  are  derivatives  of  anilin  obtained  by  replacing  am- 
monia or  amido  H  by  alcohol  radicals  or  acid  radicals.  Ace- 
tanilid,  or  phenyl  acetamid, 

[H 

NJC6H5 
[C2H30 

is  prepared  by  boiling  anilin  with  glacial  acetic  acid.  It  appears 
in  white,  unctuous  crystals,  sparingly  soluble  in  H20,  more 
freely  in  alcohol.  On  warming  with  HC1  it  is  decomposed  into 
anilin  and  acetic  acid. 

Experiment. — Prove  presence  of  anilin  in  acetanilid  by  heating  to- 
gether a  mixture  of  equal  parts  of  acetanilid  and  powdered  NaHO.  After 
a  few  minutes  invert  test-tube  and  allow  oily  globules  of  anilin  to  run 
out,  keeping  up  the  warming  process. 

Identification  of  Acetanilid. — Boil  0.1  gm.  with  1  c.c.  of  HC1  and 
then  add  1  c.c.  each  of  saturated  phenol  solution  and  saturated  solution 
of  bleaching  powder.  A  cloudy,  red  mixture  is  formed,  which  turns  dark 
blue  on  supersaturating  with  NH4HO. 

Exalgin,  or  methyl  acetanilid,  is  another  pain-reliever,  sol- 
uble in  alcohol. 

Amido-acids  are  acids  in  which  1  atom  of  H  has  been  re- 
placed by  KE2.  They  possess  both  acid  and  basic  properties. 
Amido-acetic  acid  (glycin,  glycocoll)  has  the  formula  CH2.NH2.- 
COOH.  Amido-formic,  or  carbamic,  acid,  NH2.COOH,  is  pres- 
ent as  a  salt  in  ordinary  ammonium  carbonate.  It  is  formed 
by  direct  union  of  C02  and  NH3, — C.NH4.NH202.  Leucin  is 
amido-caproic  acid:  C3H10.NH2.COOH.  Like  its  congener, 
tyrosin,  it  is  a  product  of  albuminous  decomposition  in  the  in- 
testines. 


240  THE  CARBON  COMPOUNDS. 

PYRIDINS. 

These  tertiary  monamins  are  colorless  liquids,  insoluble  in 
water,  but  soluble  in  alcohol,  ether,  and  fixed  oils.  Pyridin, 
C5H5N,  is  present  in  bone-oil,  coal-tar  naphtha,  and  tobacco- 
smoke.  It  has  a  sharp,  characteristic  odor.  Pyrrol,  C4H5N,  is 
also  in  coal-tar  and  bone-oil.  lodol,  C4I4NH,  is  a  light-brown, 
.odorless,  tasteless  powder  containing  89  per  cent.  I.  It  is  de- 
rived from  pyrrol  by  treating  with  I  in  presence  of  oxidizing 
agents.  It  is  used  as  a  substitute  for  CHI3,  and  is  not  toxic. 

Quinolm,  or  chinolin,  C9H7N,  is  prepared  by  distilling 
quinin  or  cinchonin  with  potash.  It  corresponds  with  naph- 
talin  in  which  one  CH  group  is  replaced  by  N". 

Kairin,  C10H13.NO.HC1,  is  the  hydrochlorid  of  methyl-oxy- 
chinolin-hydrid.  It  appears  in  white  crystals  soluble  in  6  H20 
or  20  alcohol. 

Thallin,  C10H1:LNO,  or  tetra-hydro-paramethyl-oxyquinolin, 
is  a  white,  aromatic,  crystalline  substance,  generally  soluble. 
It  is  colored  a  bright  green  by  Fe2Cl6  and  other  oxidizing 
agents. 

AZO  AND  DIAZO  COMPOUNDS. 

The  group  —  N"  =  N  —  links  an  alkyl  to  an  acid  radical 
in  diazo;  two  alkyl  radicals  in  azo  compounds.  These  com- 
pounds are  colorless,  crystalline  substances,  soluble  in  water, 
and  are  formed  by  treating  aromatic  amins  with  HN02.  From 
azo-benz€ne,  C6H5  —  N  =  N  —  C6H5,  the  beautiful  azo  dyes  are 
derived. 

HYDEAZINS. 

These  are  derivatives  of  hydrazin,  or  diamin,  NH2  —  NH2, 
a  colorless,  stable,  alkaline  gas,  and  are  formed  by  replacing 
H  with  alkyl  radicals. 

Phenyi-hydrazin,  C6H5  —  NH  —  NH2,  prepared  by  reduc- 
tion of  diazo-benzene,  is  a  colorless,  oily  liquid,  soluble  in  alco- 
hol and  ether,  and  a  powerful  reducing  agent,  forming  char- 
acteristic crystalline  compounds  called  osazones  with  various 
sugars,  and  hydrazones  with  aldehyds. 

Antipyrm,  or  phenazone  (phenyl-dimethyl-pyrazolon),  C1±- 
H12N20,  is  derived  from  phenyl-hydrazin  by  heating  with  di- 
acetic  ether  [(C2H302)2C2H50],  forming  phenyl-methyl-pyraz- 
olon,  which  is  then  made  to  take  up  another  methyl  group  in 
place  of  H.  Antipyrin  appears  in  white  crystals,  very  soluble 
in  H20  and  other  solvents. 


ALKALOIDS.  241 

Identification  of  Antipyrin.— Fe2Clc  gives  deep  red;  HNO3  yellow, 
then  intense  red  on  warming;  KNO2  and  HC2H3Oa  (a  few  drops  of  each) 
give  an  intense-green  color. 

NITRILS  AND  CARBYLAMINS. 

These  are  isomeric  compounds  of  organic  radicals  with 
CN.  Nitrils,  or  cyanids.  have  the  general  formula  R  —  CEEEN; 
carbylamins,  or  isocyanids,  B —  NE=C.  The  nitrils  are  vola- 
tile liquids  or  solids,  yielding  organic  acids  when  heated  with 
H20  in  presence  of  mineral  acids  or  alkalies:  e.g.,  CH3CN 
+  2H20  =  CHg.COOH  +  NH3.  Hence  they  correspond  with 
acid  oxids  or  anhydrids.  They  may  be  formed  by  heating  alkyl 
iodids  with  KCN. 

Fulminic  acid,  C2N2H202,  is  very  unstable.  Mercuric  ful- 
minate is  made  by  adding  alcohol  to  a  solution  of  Hg  in  HN03, 
and  is  used  as  an  explosive  in  percussion-caps,  developing  a 
pressure  of  43,000  atmospheres  by  detonating  in  its  own  vol- 
ume. 

The  carbylamins  are  marked  by  a  disgusting  odor  and  are 
formed  by  heating  hydrocarbon  iodids  with  AgCN.  When 
heated  with  H20  and  mineral  acids  they  form  amins  and  or- 
ganic acids:  e.g., 

CH3NC  +  2H20  =  CH3NH2  +  HCOOH 

The  isosulphocyanates,  or  mustard-oils,  RNCS,  break  down 
into  an  amin,  H2S,  and  C02  on  treating  with  H20  and  alkalies. 
The  most  important  member  of  this  group  is  allyl  sulpho- 
cyanate,  C3H5NCS,  found  in  mustard-seed. 

ALKALOIDS. 

Alkaloids  are  physiologically  active  vegetable  (or  animal) 
nitrogenous  principles,  or  natural  organic  bases,  derived  from 
pyridin  (C5H5N),  chinolin  (C9H7N),  and  isochinolin.  The 
liquid  and  volatile  alkaloids  are  amins;  the  solid  non-volatile, 
amids  (these  contain  0).  The  latter  is  much  the  larger  class. 
Their  names  all  end  in  in  (or  ine),  English;  ina,  Latin.  The 
vegetable  alkaloids  exist  in  combination  with  tannic,  malic,  *. 

meconie,  H3C7H07  (opium),  kinic  (cinchona),  and  other  acids. 
They  are  extracted  from  the  comminuted  plants  by  dissolving^ 
out  in  H20  or  alcohol,  or  by  treating  with  dilute  acids,  then 
with  CaO  or  MgO,  and  then  dissolving  in  alcohol,  ether,  chlo- 
roform, or  dilute  acids.  They  are  generally  white,  bitter,  and 
insoluble  in  H20,  but  soluble  in  other  solvents.  Their  salts  are 


242  THE  CARBON  COMPOUNDS. 

formed  by  direct  addition  of  the  acid;  they  are  more  soluble  in 
water  and  in  alcohol;  hence  are  employed  in  medicine  rather 
than  the  simple  alkaloid.  Alkaloids  and  alkaloidal  salts  are  in- 
compatible with  their  reagents  and  with  bases,  carbonates,  and 
bicarbonates.  Many  of  them  are  poisonous.  The  chemic  anti- 
dote for  all  is  tannin  or  well-diluted  K2Mn208  (grain  for  grain 
of  poison). 

Test  Precipitants. — 1.  Taimic  acid:  Resulting  tannates  are  diffi- 
cultly soluble  in  cold  water,  but  soluble  in  alcohol  or  excess  of  tannic 
or  other  acids. 

2.  Haloid   salts   of  Hg:     Double   nearly   insoluble   salts.     Mayer's 
solution   [HgI2(KI)2]   consists  of  13  V»  gm.  of  HgCl2  and  50  gm.  KI  in 
1000  c.c.  of  H20.     It  ppts.  all  the  alkaloids. 

3.  Picric  acid:    Cinchona  bases  especially. 

4.  Phosphomolybdic   and   phosphotungstic   acids:     Ppt.   great   ma- 
jority of  alkaloids. 

5.  Potassium  chromate  and  dichromate:    Ppt.  concentrated  aqueous 
solutions  as  chromates. 

6.  Chlorids   of  Au  and  Pt:    Crystalline  double  salts,  with  many 
alkaloids. 

Color-reactions.— Dehydration :    H2S04,  ZnCl2,  P2O5. 
Oxidation:    HNO3,  Cl,  Br,  NaCIO;  H2S04  and  KC1O3  or  K2Mn2O8; 
chromic,  molybdic,  iodic,  and  tungstic  acids. 

Special  reactions:    Fe2Cl6,  HC1,  H2S04,  sugar. 

VOLATILE  ALKALOIDS. 

These  are  colorless,  oily  liquids,  and  turn  brown  on  ex- 
posure to  the  air.  Coniin  is  marked  by  a  repulsive  odor,  and 
is  obtained  from  hemlock-fruit.  It  acts  as  a  motor  paralyzant 
poison.  Nicotin,  C10H14N2,  is  the  poisonous  principle  of  to- 
bacco, in  which  it  is  present  to  the  extent  of  1  to  7  per  cent. 
of  dry  leaf,  in  combination  with  malic  and  citric  acids.  It  has 
a  peculiar  strong  odor.  When  tobacco  is  smoked  the  nicotin 
is  converted  largely  into  pyridin.  Nicotin  is  a  narcotic  poison, 
and  1  m.  has  proved  fatal. 

Identification  of  Nicotin.— Violet  with  HC1;  orange  with  HN03. 

Lobelin,  from  lobelia,  or  Indian  tobacco,  has  an  odor 
like  tobacco  mixed  with  honey.  Spartein,  from  the  leaves  and 
branches  of  broom,  is  an  odorless,  very  bitter  cardiac  tonic. 
Spigelin,  from  spigelia,  or  pinkroot,  is  used  as  a  vermifuge  for 
round-worms. 

NON-VOLATILE   ALKALOIDS. 

Solanaceae. — These  are  closely  allied  mydriatics  and  deliri- 
ants,  having  the  formula  C17H23N"03.  They  quicken  the  pulse 
and  respiration,  and  may  cause  death  by  overstimulation,  lead- 


ALKALOIDS.  243 

ing  to  paralysis.  The  most  potent  and  important  is  atropin, 
from  Atropa  belladonna.  Its  sulphate  is  commonly  employed. 
Henbane  has  two  important  alkaloids,  hyoscin  and  hyoscyamin, 
duboisin  being  another  name  for  both;  the  hydrobromate  is 
the  common  salt.  Daturin  is  obtained  from  stramonium;  sola- 
nin  from  bitter-sweet  and  potato-sprouts;  and  scopolamin 
(identic  with  hyoscin)  from  scopolia.  Baryta-water  decom- 
poses atropin  into  tropin,  C8H15N03,  and  this  furnishes  homat- 
ropin. 

Identification  of  Atropin. — Boiling  with  dilute  HaS04  gives  an 
orange-flower  odor,  which  is  changed  to  bitter-almond  odor  and  green 
color  on  adding  K2Cr2O7. 

Cinchona  Group. — Peruvian  bark  contains  at  least  5  per 
cent,  of  alkaloids,  of  which  one-half  should  be  quinin.  Of  the 
thirty-two  cinchona  alkaloids,  the  chief  four  are  quinin  (C20- 
H24N202),  quinidin,  cinchonin,  and  cinchonidin.  These  are  all 
effective  febrifuges  and  antiperiodics.  The  principal  salts  of 
quinin  are  the  sulphate,  bisulphate,  hydrobromate,  hydrochlo- 
rate,  and  valerianate.  The  neutral  sulphate  is  soluble  in  740 
H20  or  65  alcohol.  The  hydrochlorate  is  most  soluble:  in  34 
of  water.  The  cumulative  effects  of  quinin  are  due  to  rapid 
absorption  (fifteen  minutes)  and  slow  elimination  (two  or  three 
days). 

Identification  of  Quinin. — Solutions  in  excess  of  dilute  H2SO4  show 
a  strong  fluorescence. 

To  10  c.c.  solution  of  quinin  add  2  m.  of  Br  water  and  excess  of 
NH4HO,  and  get  emerald  green  of  thalleioquin. 

Herapathit  Test. — Dissolve  Y2  gm.  of  alkaloid  in  15  c.c.  of  alcohol 
of  0.83  sp.  gr.,  diluted  with  5  c.c.  of  water,  and  acidulate  fluid  with  2 
c.c.  of  10-per-cent.  H2SO4;  add  to  this  solution  of  0.2  gm.  of  I  in  10  c.c. 
of  alcohol  (0.83  sp.  gr.) ;  warm  mixture  slightly  and  allow  to  cool.  Note 
the  quite  insoluble  microcrystalline  ppt.:  dark  green  —  quinin ;  red  = 
quinidin;  yellow  —  cinchonidin;  no  ppt.  =  cinchonin. 

Opium,  or  Thebaicum,  Group. — Of  the  seventeen  alkaloids 
extracted  from  poppy,  morphin,  C17H19N03  (10  to  14  per  cent.), 
is  chief.  Narcotin,  an  hypnotic,  constitutes  4  per  cent.;  papav- 
erin,  a  narcotic,  1/2  to  1  per  cent.;  codein,  an  analgesic,  0.2 
to  0.8  per  cent.;  and  thebain,  a  tetanic  convulsant,  0.2  to  0.5 
per  cent.  Opium  may  be  deodorized  with  ether,  which  dissolves 
out  narcotin.  The  sulphate  is  the  common  salt  of  morphin. 
It  dissolves  in  24  H20,  702  alcohol.  The  hydrochlorate  of 
morphin  on  heating  with  HC1  is  dehydrated  into  the  emetic, 
apomorphin  hydrochlorate.  Solutions  of  this  on  exposure  to 
air  turn  green.  Other  artificial  derivatives  are  heroin  (diacetyl- 


244  THE  CARBON  COMPOUNDS. 

rnorphin),  dionin  (hydrochloric!  of  monoethyl-ester  of  morphin), 
and  peronin  (hydrochlorid  of  benzyl  ether  of  morphin). 

Identification  of  Morphin. — HN03  gives  a  red  color,  fading  to 
yellow  and  discharged  by  reducing  agents.  Fe2Cl6  colors  blue,  turning 
green. 

Identification  of  Codein. — This  shows  a  claret-red  color  with  Br 
water  on  shaking  and  adding  NH4HO. 

Strychnos  Alkaloids. — Strychnin  and  brucin  are  found  in 
the  seeds  of  S.  nux  vomica  and  8.  ignatia  and  in  S.  tiente^  the 
deadly  upas-tree  root-bark  of  Java,  used  as  an  arrow-poison. 
Strychnin  is  so  bitter  as  to  be  perceptible  in  a  dilution  of  1  to 
700,000.  Its  usual  salt  is  the  sulphate,  It  produces  death  by 
asphyxia  from  tetany  of  the  respiratory  muscles.  (Smallest 
fatal  dose,  V4  grain;  time,  5  minutes  to  6  hours.)  Brucin  is 
similar,  but  milder  in  action. 

Identification  of  Strychnin. — H2S04  and  a  crystal  of  K2Cr207  give 
blue,  running  through  a  rainbow  of  colors  to  red-yellow. 

Identification  of  Brucin. — It  turns  blood-red  with  HNO3,  yellow 
on  heating,  violet  on  adding  Na2S2O3. 

Physostigmin,  or  Eserin. — This  myotic  is  extracted  from 
Calabar  bean.  The  chief  salts  are  the  salicylate  and  sulphate. 
It  produces  death  in  the  same  way  as  strychnin. 

Cocain. — The  hydrochlorate  is  readily  and  generally  sol- 
uble. It  is  a  local  anesthetic.  Less  than  a  grain  has  produced 
death  by  respiratory  paralysis  or  tetanic  spasm  of  the  heart. 
Eucain  is  a  valuable  and  less  toxic  derivative;  #-eucain  is  less 
irritant  than  a-eucain. 

Pilocarpin. — This  is  a  valuable  sudorific  extracted  from 
jaborandi-leaves.  The  nitrate  and  hydrochlorate  are  the  salts 
in  use.  Jaborin,  from  the  same  source,  is  less  important. 

Aconitin.  —  This  alkaloid  is  present  in  monk's-hood  or 
wolf's-bane.  One-twelfth  grain  has  caused  death  by  paralysis 
of  heart  and  respiration. 

Veratrin. — Veratrum  (poke-root,  hellebore)  contains  jervin, 
cevadin,  pseudojervin,  protoveratrin,  etc. 

Identification  of  Veratrin. — H2S04  gives  a  yellow  color,  turning 
scarlet  and  violet-red. 

Hydrastis  Group. — Berberin  is  a  yellow  alkaloid  found  in 
barberry,  golden-seal,  etc.  Hydrastin  is  the  white  alkaloid  of 
hydrastis;  it  oxidizes  to  yellow  needles  of  hydrastinin.  These 
three  alkaloids  are  astringent  and  antiseptic. 

Piperin  appears  in  pale-yellow  crystals,  and  is  present  in 
both  black  and  white  peppers.  The  ipecac  alkaloids  are  emetin 


ALKALOIDS.  245 

and  cephalin.  Theobromin  is  present  in  cacao-seeds  (1  or  2 
per  cent.)  and  kola-nuts.  Caffein,  thein,  or  guaranin  (methyl- 
theobromin)  is  the  active  principle  of  tea  (2  to  4.5  per  cent.), 
coffee  (1.2  per  cent.),  mate  (0.2  to  2  per  cent.),  guarana  (5  per 
cent.),  and  kola-nut.  Aspidospermin  is  found  in  quebracho. 
Gelsemium  contains  the  alkaloids  gelsemin  and  gelseminin. 
The  Anhalonium  Lewinii,  a  member  of  the  cactus  family,  con- 
tains an  hypnotic  alkaloid,  pellotin,  and  an  intoxicating  alkaloid 
called  mezcalin. 


ANIMAL  ALKALOIDS. 

Ptomains  are  products  of  putrefaction  of  albuminous  sub- 
stances in  dead  or  living  bodies.  Like  vegetable  alkaloids,  they 
are  solid  or  liquid,  fixed  or  volatile,  amorphous  or  crystalline, 
bitter  or  tasteless.  Their  odor  may  be  wanting,  or  sweet  and 
aromatic,  or  cadaveric.  In  chemic  reactions  they  correspond 
closely  to  vegetable  alkaloids,  for  which  they  may  be  mistaken. 
They  differ  from  most  vegetable  alkaloids  in  being  optically 
inactive. 

The  methylamins  and  ethylamins  are  not  poisonous.  The 
following  are  all  toxic:  Putrescin  and  cadaverin,  in  corpses; 
tyrotoxicon,  C6H5IS[2,  in  putrid  cheese,  milk,  and  cream  (ice- 
cream, cream-puffs);  muscarin,  in  decomposed  flesh  and  fungi; 
mytilotoxin,  C6H15N02,  in  oysters  and  other  mussels;  neurin, 
in  decomposing  meat;  and  cholin,  in  animal  tissues,  hops,  and 
ergot. 

Leucomains  are  formed  in  the  living  body  by  retrograde 
metamorphosis  with  insufficient  0.  They  are  much  increased 
in  anemia,  chlorosis,  and  constipation.  They  are  mostly  non- 
toxic. 

Toxins  are  poisonous  bases  or  albumins,  the  products  of 
specific  bacteria  and  the  direct  cause  of  most  infectious  dis- 
eases. Diphtheria  poison  is  a  white,  amorphous  toxalbumin. 
The  typhoid  bacillus  produces  typhotoxin,  C2H17N"02.  The 
tetanus  bacillus  produces  two  toxins,  tetanin  and  spasmotoxin, 
both  of  which  excite  tonic  and  clonic  convulsions. 

Soluble  antitoxins  of  unknown  composition  are  set  free 
from  the  white  blood-cells  and  the  fixed  tissues.  They  antag- 
onize the  toxins  and  account  for  artificial  immunity.  A  normal 
serum  neutralizes  ten  times  as  much  toxin.  An  antitoxic  unit 
neutralizes  enough  toxin  (when  injected  at  the  same  time)  to 
kill  one  hundred  guinea-pigs.  Very  concentrated  antitoxic 
serums  are  now  in  use  (3000  units  per  c.c.). 


246 


THE  CARBON  COMPOUNDS. 


PROTEINS. 

Kepresentatives  of  this  group  are  essential  parts  of  proto- 
plasm and  of  animal  and  vegetable  fluids.  They  are  very  com- 
plex substances  with  hundreds  or  thousands  of  atoms  in  a  mole- 
cule, chiefly  C  (50  to  55  per  cent.),  H  (7  per  cent.),  0  (20  to  24 
per  cent.),  N  (15  to  18  per  cent.),  and  S  (in  most,  1/3  to  2  1/2 
per  cent.);  P  and  Fe  in  a  few.  The  average  composition  is  rep- 
resented by  the  formula  C144H224N36044S2.  They  yield  NH3, 
H2S,  fatty  acids,  amido-acids,  etc.,  on  decomposition. 

Experiment. — Prove  presence  of  S  in  white  of  egg  by  boiling  with 
Pb(HO)2  [made  by  adding  NaHO  to  Pb(C2H302)2  solution  till  ppt.  first 
formed  has  dissolved]. 

Proteins  are  elaborated  by  plants  from  NH3,  nitrates,  ni- 
trites, etc.  They  are  stored  up  as  minute  granules  (sometimes 
crystalline)  in  seeds,  roots,  and  tubers.  Animals  derive  all 
their  proteins  from  vegetable  sources,  and  eventually  break 
them  down  into  simpler  compounds. 

Proteins  are  colorless,  odorless,  nearly  tasteless  substances, 
amorphous  and  non-dialyzable  (except  peptons)  and  levorota- 
tory.  They  easily  putrefy,  and  are  readily  coagulated  by  heat, 
mineral  acids,  alcohol,  and  mineral  salts.  They  are  converted 
by  digestive  juices  into  acid  or  alkali  albumins,  then  albumoses, 
and  finally  peptons.  On  heating  dry  they  char  and  give  forth 
the  odor  of  burnt  horn  or  wool.  The  classes  of  proteins  and 
the  chief  members  of  each  class  are  shown  in  the  following 
table.  It  is  a  noteworthy  fact  that  the  same  protein  may 
exhibit  different  properties  under  varying  conditions  and  in 
different  parts  of  the  body. 


Native  Albumins. — Sol- 
uble in  distilled 
water  ;  coagulated  by 
heat. 


Serum-albumin — 4  to  5  %  in  human  blood  ;  used 
in  dyeing,  calico-printing,  and  refining  cane- 
sugar. 

Cell -albumin. 

Muscle-albumin  (myoalbumin). 

Milk-albumin  (lactalbumin) — 0.75%  in  cows' 
milk  ;  1.25  in  woman's  milk. 

Egg-albumin  —  white  of  egg  ;  pptd.  by  ether 
(serum-a.,  not)  or  by  HC1  (ppt.  not  soluble  in 
excess  as  with  serum-a. )  ;  used  as  a  glaze  and  a 
vehicle  for  colors  in  calico-printing,  for  soften- 
ing leather,  and  in  book-binding  and  photog- 
raphy. 

Plant-albumin — flocculi  on  heating  plant-juices  ; 
leucosin  in  wheat,  rye,  barley. 

Paralbumin  ( pseudomucin )  —  found  in  fluid  of 
ovarian  cysts. 


PROTEINS. 


247 


Globulins. — Insolubl  e 
in  pure  H2O  ;  soluble 
in  dilute  solutions  of 
neutral  salts  (pptd. 
by  excess)  ;  coagu- 
lated by  heat  ;  pptd. 
by  current  of  CO2,  by 
diluting  freely  with 
H2O,  or  by  removing 
salt  by  dialysis. 


Serum -globulin  (paraglobulin,  fibrinoplastin ) — 
2.2  %  of  blood-plasma. 

Fibrinogen — pptd.  by  saturating  with  NaCl  ; 
changed  to  fibrin  by  f. -ferment. 

Myosinogen  (muscle-plasma) — yellowish  fluid  clot 
after  death  (rigor  mortis)  :  extracted  with  10$ 
NH<C1,  pptd.  by  excess  of  H2O. 

Cell-globulin. 

Crystallin  (globulin) — 25  %  of  crystalline  lens. 

Globin— insoluble  proteid,  from  spontaneous  de- 
composition of  hemoglobin. 

Plant-globulin  —  hemp,  nuts,  castor-bean,  etc.  ; 
edestin  in  cereals. 


Derived  Albumins  (Al- 
buminates).  —  Sol- 
uble ( when  freshly 
pptd. )  in  dilute  acids 
and  alkalies  ;  pptd. 
by  neutralizing. 


Acid  albumins — slightly  alkaline  reaction  ;  syn- 
tonin  formed  in  stomach  by  HC1. 

Alkali  albumins — slightly  acid  reaction. 

Plant-caseins,  or  legumin — in  almonds,  oats,  len- 
tils, pease,  and  beans  (nearly  25  %}\  insoluble 
in  dilute  alcohol. 


Fibrins. — Slowly  s  o  1  - 
uble  in  dilute  acids  or 
10  %  NaCl. 


Fibrin — produced  by  clotting  of  blood,  lymph,  or 

chyle  ;  elastic,  gelatinous,  fibrillar. 
Gluten-proteins—soluble  in  dilute  alcohol ;  best 

obtained  by  kneading  wheat-flour  on  a  sieve  ; 

starch  passes  through  ;    sticky,  elastic  gluten 

remains. 
Zein  is  a  fibrin-like  proteid  in  maize. 


Coagulated    Proteids.  —  "] 

Dissolved    difficultly   I  Paracasein  —  produced   by    action  of  rennin  on 

by  strong  hot  acids  or   \  casein— milk-curds, 

alkalies  ;  readily  di-  Heat  or  acid  products -boiled  egg,  for  instance. 

gested.  J 


A Ib umoscs  (Prote- 
oses,  Propeptons). 
—  All  soluble  in 
dilute  NaCl,  and 
some  in  H2O  ;  not 
coagulated  by 
heat. 


Anti-   (changed  to  peptons)  : 

(Protalbumose. 
Hetero-albu- 
mose  (dysal- 
buniose ) . 

~)  Hemi-  (changed  to  leucin  and 
tyrosin ) ;  secondary  =  deu- 
tero-albumose. 

Histon  is  a  poisonous  albumose 
from  the  nuclei  of  cells. 


Hemi-  and  anti- 
groups  separated 
by  3#  H2SO4, 
which  throws 
down  gelatinous 
mass  of  anti-albu- 
mid,  insoluble  in 
dilute  acids, 
readily  soluble 
in  dilute  Na2CO3. 


248 


THE  CARBON  COMPOUNDS. 


Peptons. — Generally   f 
soluble,  very  hygro-  I   Anti- 
scopic,  and  quite  dif-  1   Hemi- 
fusible  ;  bitter  taste.    [ 


Final  products  of  digestion  ;  pptd.  only 

, ;    ;_.  HI 

HgCl2 


by  tannin,  alcohol,  (KI)2,  HgI2,  and 


Hemipeptons  are  converted  into  leucin 
and  tyrosin  in  bowels  ;  anti-,  not. 

Both  peptons  and  albumoses  may  be 
formed  by  putrefaction. 


Compound  Proteins,  or 
Proteids.  —  Yield  on 
cleavage  (boiling 
with  dilute  mineral 
acids)  simple  proteins 
and  non-proteins. 


Glycoproteids, 
or  metalbu- 
mins  (acid, 
viscid, 
thready). 


Mucin— mucous  membranes, 
saliva,  tendons,  umbilical 
cord  ;  pptd.  by  Pb(  C2H3O2  )2, 
HC2H3O2  (if  neutral  salts  ab- 
sent), or  alum  ;  soluble  in  di- 
lute alkalies  ;  swells  in  H2O 
and  dissolves  in  excess; 
cleaves  into  albumin  and  a 
carbohydrate-reducing  agent 
—no  S.  . 

Mucoids — cartilage  and  ovarian 
liquids  ;    similar  cleavage 
products  to  mucin,  but  not 
pptd.  by  HC2H3O2. 
Nucleo-proteids  (nuclein   and  globulin)— gland- 
cells  ;   viscid  ;  acid  reaction  ;   soluble  in  H2O  ; 
thrown  out  of  solutions  by  HC2H3O2  or  neutral 
salt  solutions. 

Nucleins— chief  component  of  cells  ;  rich  in  P  (as 
H3PO4)  in  combination  with  albumin  or  a 
nuclein  base  (adenin,  guanin,  xanthin,  hypo- 
xanthin)  ;  readily  soluble  in  dilute  alkalies, 
not  attacked  by  gastric  juice. 

Hemoglobins  (hematoglobulin, 
hematocrystallin )  —  oxygen- 
carriers  ;  contain  Fe  ;  soluble 
in  H20  ;  C000H960N15,0179FeS3 
Vitellin  — 15     %     of    yelk    of 
hens'  eggs  ;   P  and  globulin 
I       and  nuclein  radical. 

Caseinogen  ( paranucl co-albumin )  — 1  %  of  woman 's 
milk,  3  %  of  cows' ;  coagulated  by  rennet,  form- 
ing calcium  caseate  ;  pptd.  by  excess  of  neutral 
salts  or  by  acid  (removes  combining  alkali)  ; 
contains  P,  albumin,  and  a  nuclein  radical. 
Lecith-albumins  —  milk,  stomach,  and  liver  ;  al- 
bumin and  phosphorized  fat. 

Lardacein  (amyloid  substance) — friable,  trans- 
lucent, pathologic  product  in  viscera  ;  colored 
red  by  I,  blue  or  violet  by  I  and  dilute  H2SO4  ; 
soluble  only  in  strong  acids  or  alkalies. 


Chromo-pro- 
teids. 


PROTEINS. 


249 


Albuminoids,  or  Gelat- 
inoids.  —  In  bones 
and  protective  parts  ; 
generally  insoluble 
and  indigestible  ;  less 
C  and  S  and  more  N 
than  in  other  pro- 
teins. 


Collagens  —  white  connective  tissues,  tendons, 
skin,  and  bones;  gelatin  (soluble  in  warm 
water)  is  hydrated  ossein  or  collagen  ;  gliadin 
is  plant-gelatin  ;  the  only  digestible  albumi- 
noids ;  tannin  prevents  putrefaction  ;  purest 
source  of  gelatin  is  isinglass,  or  ichthyocolla 
(used  in  court-plaster)  ;  glue,  or  size,  is  impure 
gelatin  from  hides  and  parings  ;  liquid  glue,  a 
solution  in  HC2H3O2. 

Chondriu — in  cartilage  or  gristle. 

Keratins  —  horny  parts :  nails,  hair,  horns, 
feathers  ;  contain  large  amount  of  loosely  united 
S  ( 4  or  5  % )  ;  neurokeratiii  in  neuroglia  of 
nerves. 

Eleidin  —  intermediate  between  keratins  and 
protoplasm  ;  stratum  granulosum  of  skin. 

Elastins — yellow  connective  tissue  and  ligaments  ; 
contain  no  S  ;  hard  and  brittle  when  dry  ;  con- 
verted during  digestion  into  elastoses  (like 
albumoses). 

Fibroin— chief  constituent  of  silk  ;  covered  with 
a  glue,  sericin. 

Chitins— skeletons  of  invertebrata. 

Spongin — chief  ingredient  of  sponges. 

Enzymes— nucleo-proteids  probably  ;  optically  act- 
ive (see  "Ferments"). 


General  Protein  Reactions. — Use  2-per-cent.  solution  of  egg-albu- 
min and  of  pepton;  a  number  of  tests  should  always  be  employed. 

Biuret  Test  (Diamid  Croup). — Add  an  equal  volume  of  strong 
KHO,  heat  to  boiling,  and  add  1  or  2  drops  of  very  dilute  CuS04.  All 
proteins  give  a  violet  color  except  gelatin  (bluish  violet  in  the  cold)  and 
albumoses  and  peptons  (purple-red  in  cold). 

Ninon's  Reaction  (Oxyphenol  Group). — The  reagent  is  prepared  by 
dissolving  Hg  in  an  equal  weight  of  HNO3,  keeping  cold  at  first,  then 
using  gentle  heat,  and  when  dissolved  adding  2  volumes  of  H2O.  A  few 
drops  added  to  albumin  solutions  give  a  white  ppt.,  turning  red  on 
boiling. 

Xanthoproteic  Reaction  (Nitro-products  of  Phenol  and  Tyrosin). — 
Add  -an  equal  volume  of  HN03  and  boil,  getting  a  yellow  ppt.  or  solution, 
which  turns  orange-yellow  on  cooling  and  adding  excess  of  NaHO. 

Adamkiewicz's  Reaction  (Indol  and  Skatol). — Mix  2  c.c.  of  H,S04 
with  4  c.c.  of  glacial  acetic  acid  and  add  a  fragment  of  the  dry  protein 
or  a  drop  of  concentrated  solution.  On  slightly  warming,  a  beautiful 
reddish  violet  color  appears. 

Licbermann'8  Reaction  (Non-aromatic  Groups). — To  2  or  3  c.c.  of 
HC1  add  1  or  2  drops  of  undiluted  egg-albumin,  and  boil  several  minutes, 
getting  a  pink  or  violet  color. 

Ammonia  Test. — Mix  dry  protein  with  excess  of  soda-lime,  and  heat 
in  a  dry  test-tube;  test  vapors  for  NH3. 

Precipitation  Reactions. — By  coagulation,  which  is  favored  by  pres- 
ence of  NaCl,  especially  albumoses. 

Heat. — Ppts.  serum-albumin  about  50°  (75°  if  salt  be  present) ; 
plant-albumin  at  61°  to  63°;  myosin  (40°  to  50°  in  salt  solution)  and 
vitellin  (75°)  and  globulin,  but  not  acid  or  alkali  albumin,  albumoses 
(clears  up  ppt.),  peptons,  or  gelatin. 


250  THE  CARBON  COMPOUNDS. 

Acids. — Nitric  best  by  contact — on  boiling,  acid  albumin  forms  and 
ppt.  dissolves.  Phosphotungstic  and  phosphomolybdic  acids  ppt.  all 
proteins  in  presence  of  HC1. 

Strong  HC2H302  and  K4FeCy6  (10  per  cent.). — A  very  delicate  test 
for  all  proteins  except  peptons:  use  1  or  2  drops  of  each  to  5  c.c.  of  solu- 
tion. 

Metallic  Salts.—  (KI)2HgI2  and  HgCl2  (ppt.  dissolved  by  NaCl  solu- 
tion). 

Br  Water. — Sticky  yellow  ppt.  with  gelatin. 

Alcohol. — In  large  excess  ppts.  all  proteins,  and  after  a  time,  if 
strong,  coagulates  them. 

MgSO±. — Saturation  ppts.  globulins,  not  albumins. 

(NHJ2804. — Heating  with  an  equal  volume  of  saturated  solution 
ppts.  all  except  peptons. 

Tannin. — Ppts.  pepton  as  well  as  others. 

Separation  of  Chief  Proteins. — Serum-globulin  is  pptd.  by  saturat- 
ing with  MgS04  at  30°. 

Serum-albumin  is  pptd.  from  filtrate  by  saturating  with  Na2S04 
at  40°. 

Albuminates  are  pptd.  by  neutralizing  second  nitrate. 

Albumoses  are  pptd.  by  saturating  third  nitrate  with  (NH4)2SO4. 

Peptons  are  pptd.  by  adding  tannin  to  fourth  filtrate. 

Gelatin  in  dilute  solution  resembles  pepton,  but  is  pptd.  easily  with 
alcohol  or  by  saturating  with  (NH4)2SO4. 

Metallic  salts  are  commonly  absorbed  as  albuminates.  The 
albuminate  of  Fe  (ferrated  albumin)  appears  in  red-brown  sol- 
uble scales  or  powder  and  contains  about  20  per  cent,  of  Fe. 
It  is  made  by  combining  solution  of  ferric  oxychlorid  with  dried 
egg-albumin  in  sufficient  water,  neutralizing  with  NaHO,  and 
washing  and  drying  on  glass  plates. 

Attempts  at  the  synthetic  production  of  proteins  (chiefly 
from  their  digestion  products)  have  thus  far  yielded  interest- 
ing, but  not  practical,  results.  Lilienfeld  suspended  glycocoll 
in  C2H5HO,  passed  dry  HC1  gas  through  the  mixture,  and  then 
treated  with  Ag20,  forming  an  ester,  which  broke  down  into 
alcohol,  glycocoll  anhydrid,  and  a  solid  base  responding  to  the 
biuret  test.  The  carbonate  of  this  base,  C5H9N304,  when 
heated  with  water,  threw  down  a  gelatinous  ppt.,  corresponding 
closely  in  physic  properties  and  chemic  reactions  to  gelatin. 
He  has  also  found  that,  by  combining  and  condensing  the  esters 
of  leucin,  tyrosin,  and  aspartic  acid  with  the  above-named  base, 
several  albuminous  bodies  could  be  formed.  A  pseudopepton 
has  been  prepared  by  Schiitzenberger  by  heating  a  mixture  of 
amido-acid  with  10-per-cent.  urea;  then,  after  drying,  with 
1  Y2  parts  of  P205;  and  finally  pptg.  with  alcohol  and  freeing 
from  H3P04. 


FERMENTS.  251 

FERMENTS. 

These  are  substances  which  cause  selective  ("key  in  lock") 
chemic  changes,  chiefly  hydrolysis,  without  themselves  under- 
going any  appreciable  change.  They  were  so  named  because 
of  the  effervescent  effect  of  yeast  on  sugar  solutions.  They 
are  classified  as  unorganized  and  organized. 

Unorganized  ferments,  or  enzymes,  are  excreted  by  organ- 
ized ferments  or  secreted  by  living  tissue-cells.  They  exist  in 
animal  cells  in  an  inactive  state,  called  zymogens  (pepsin  as 
pepsinogen),  and  become  active  when  exposed  to  the  air  or  to 
the  action  of  acids  or  alkalies.  They  are  slowly  diffusible,  sol- 
uble in  glycerin  (when  impure)  and  water,  from  which  absolute 
alcohol,  Pb(C2H302)2,  or  (NH4)2S04  ppts.  them.  They  are 
capable  of  transforming  a  large  amount  of  the  substance  acted 
on. 

Enzymes,  as  a  rule,  act  best  at  or  near  the  temperature  of 
the  human  body.  A  low  temperature  inhibits  their  action,  and 
all  coagulate  and  lose  their  potency  when  heated  in  a  moist 
state  much  above  40°.  An  excess  of  zymolytic  products  retards 
and  stops  ferment  action  for  the  time. 

Ferments  which  break  down  proteins  into  simpler  products 
are  termed  proteolytic;  those  that  convert  amyloses  into  sugars, 
amylolytic;  and  those  that  change  more  complex  to  simple 
sugars,  glycolytic.  Proteolytic  enzymes  have  been  used  for  the 
removal  of  false  membranes. 

Of  the  vegetable  enzymes  diastase  (maltin)  is  most  impor- 
tant. It  is  derived  from  the  gluten  of  sprouting  cereals.  It 
converts  starch  (50,000  parts)  into  dextrins,  then  maltose. 
Malted  barley  contains  two  other  ferments,  the  one  acting  on 
proteins,  the  other  on  cellulose,  dissolving  the  husk.  Sweet 
extracts  of  malt  are  infusions  of  malted  barley  containing  dex- 
trins, maltose,  and  dextrose,  and  should  contain  the  active 
ferments.  Bitter  malt  extracts  are  simply  weak  beers. 

Experiment. — Make  a  little  starch  paste;  add  a  drop  of  an  I  solu- 
tion and  several  drops  of  a  good  malt  extract.  Warm  for  twenty 
minutes  at  body  temperature.  Note  changes  in  color  (dextrins)  and 
reducing  action  of  final  product  on  an  alkaline  copper  solution. 

Emulsin,  or  synaptase,  occurs  in  sweet  and  bitter  almonds 
and  other  vegetable  products.  It  is  a  white  mass,  which  con- 
verts amygdalin  into  dextrose  and  HCN".  A  similar  ferment 
has  been  found  on  parasitic  plants  growing  on  trees. 

Papain  (papayotin)  is  present  in  the  milky  juice  of  the 
pawpaw  tree.  It  is  a  white,  granular  powder,  proteolytic  in 


252  THE  CARBON  COMPOUNDS. 

action,  with  leucin  as  the  end-product.  It  also  curdles  milk. 
It  can  act  in  a  feebly  acid,  neutral,  or  alkaline  medium. 

Bromelin  is  another  proteolytic  ferment  obtained  from 
pine-apple.  Myrosin  is  the  essential  enzyme  of  mustard.  The 
yeast-plant  (baker's  or  brewer's  yeast)  produces  a  glycolytic  fer- 
ment (invertin)  which  changes  cane-sugar  to  glucose  and  which 
is  set  free  by  the  death  of  the  cells.  Zymase  is  another  yeast- 
ferment,  separated  by  pressure.  It  causes  alcoholic  fermenta- 
tion of  sucrose  and  glucose. 

Animal  ferments  are  the  essential  factors  in  digestion. 
They  are  usually  extracted  with  glycerin,  pptd.  with  absolute 
alcohol,  and  preserved  in  solution  by  antiseptics,  such  as  0.5 
per  cent.  CHC13,  5  per  cent,  thymol,  1  per  cent.  HC7H503,  and 
15  to  25  per  cent.  C2H5HO.  Or  the  digestive  juice  may  be 
treated  several  hours  with  dilute  H3P04  and  then  with  lime- 
water,  when  the  pptd.  Ca3(P04)2  drags  down  the  enzyme  me- 
chanically; the  ppt.  is  dissolved  in  HC1  and  dialyzed. 

The  proteolytic  enzymes  include  pepsin,  trypsin,  and  erep- 
sin.  Pepsin  is  secreted  by  the  stomach-glands  as  pepsinogen, 
and  requires  HC1  to  complete  and  render  it  active.  Its  action  is 
favored  by  0.1  per  cent.  NaCl  and  by  dilute  antiseptics;  re- 
tarded by  sugar,  alkalies,  regurgitated  bile,  or  metallic  salts 
(except  calomel).  The  U.  S.  P.  preparation  is  capable  of  di- 
gesting 3000  parts  of  freshly  coagulated  egg-albumin  in  six 
hours.  It  is  destroyed  when  in  solution  by  heating  to  55°. 
Trypsin  acts  on  proteins  the  same  as  pepsin,  but  more  power- 
fully. It  requires  a  slightly  alkaline  medium  (0.3  per  cent. 
Na2C03).  Erepsin  converts  peptons  and  albumoses  into  crystal- 
line and  amido-acids. 

Amylolytic  animal  ferments  include  the  ptyalin  of  saliva 
and  the  amylopsin  of  pancreatic  juice.  The  former  acts  only 
on  boiled  starch.  The  latter  is  aided  by  the  presence  of  bile, 
and  is  identic  in  action  with  vegetable  diastase,  changing  starch 
to  dextrins,  then  isomaltose  and  maltose,  and  sometimes  glu- 
cose. In  young  infants  both  these  enzymes  are  deficient. 

Experiment. — Show  amylolytic  action  of  saliva  by  chewing  an 
oyster-cracker  for  ten  or  fifteen  minutes,  testing  a  little  at  short  inter- 
vals for  dextrins  and  maltose. 

The  glycolytic  ferment  invertase  (invertin)  is  the  active 
agent  in  the  intestinal  juice,  converting  100,000  parts  of  com- 
pound sugars  to  glucose.  A  similar  ferment  exists  in  the  gas- 
tric juice.  There  are  also  glycolytic  ferments  in  the  blood  and 
other  tissues  and  oxidizing  ferments  (oxidazes)  in  the  blood. 
Maltose  and  other  enzymes  may  exert  reversed  zymolysis:  e.g., 
change  dextrose  to  maltose. 


FERMENTS.  253 

Steapsin  (pialyn,  lipase)  is  a  fat-cleaving  ferment  present 
in  the  pancreatic  juice  and  the  bile.  It  splits  oils  and  fats  into 
glycerin  and  fatty  acids.  The  latter  form  soaps  with  the  Na2- 
C03  present,  and  these  emulsify  the  remaining  fats. 

Eennin  (chymosin,  lab-ferment)  is  a  milk-curdling  ferment 
produced  by  the  stomach  and  the  pancreas,  especially  of  young 
animals.  Excess  of  acid  destroys  it.  For  the  action  of  rennin, 
as  well  as  for  the  clotting  produced  by  the  fibrin-ferment  of  the 
blood  and  myosin-ferment  of  muscles,  the  presence  of  Ca  salts 
is  necessary.  Fibrin-ferment  probably  comes  from  the  dis- 
integration of  leucocytes  and  blood-plaques  when  the  vessels 
have  been  injured. 

Histozym  is  a  ferment  in  the  blood  and  internal  organs 
which  converts  benzoic  into  hippuric  acid.  There  are  probably 
two  ferments  in  the  liver:  one  to  dehydrate  glucose  into  glyco- 
gen,  the  other  to  change  glycogen  to  glucose. 

To  explain  the  action  of  enzymes  we  may  assume  either 
that  they  combine  with  starch,  sugar,  or  proteins  to  form 
hydrates  with  H20  and  then  split  off  the  enzyme;  or  that  their 
molecular  vibrations  coincide  with  those  of  the  fermentable 
substance,  and  that  they  serve  simply  as  catalyzing  agents  to 
liberate  impulses. 

Living  or  organized  ferments  ("active  ferments")  are  low 
vegetable  micro-organisms,  mostly  bacteria,  acting  best  at  20° 
to  40°  and  causing  both  normal  (proteolytic,  amylolytic,  glyco- 
lytic,  and  fat-cleaving)  and  pathogenic  fermentation  in  the 
organism.  They  contain  fat,  cellulose,  albumin,  and  salts.  Un- 
like enzymes,  their  growth  is  checked  by  antiseptics  (1  per  cent, 
of  NaF  or  CHC13).  Heating  to  100°  kills  them  except  a  few 
spores,  and  absence  of  moisture  inhibits  their  action. 

The  yeast-fungus  (Torula,  Saccharomyces)  appears  in  oval 
budding  forms  of  several  varieties,  present  in  the  air  and  on 
fruits.  It  decomposes  95  per  cent,  of  glucose  to  alcohol,  but  is 
killed  when  the  latter  becomes  concentrated.  The  soluble  en- 
zyme invertase,  produced  by  yeast-cells,  changes  cane-sugar  to 
glucose,  which  is  further  acted  on  by  the  yeast.  CHC13  stops 
the  alcoholic  fermentation,  but  not  inversion. 

Mycoderma  aceti  ("mother  of  vinegar")  is  made  up  of 
aerobic  streptococci,  which  oxidize  alcohol  (containing  phos- 
phates and  a  little  albumin  or  NH4  salts)  to  acetic  acid.  Cer- 
tain ester-producing  bacteria  change  malt  to  wine.  The  mold, 
Mucor  mucedo,  causes  alcoholic  fermentation. 

Oidium  albicans  (thrush,  or  sprue)  is  a  mycelial  growth 
(long,  adherent  cells)  collecting  in  the  oral  cavities  of  poorly 
nourished  individuals,  and  forming  in  part  the  tartar  on  teeth. 


254:  THE  CARBON  COMPOUNDS. 

The  bacilli  lactici  and  butyrici  grow  best  without  0,  and 
cause,,  respectively,  lactic-  and  butyric-  acid  fermentation  of 
mucus,  sugars,  and  proteins.  Intestinal  colic  (from  H)  is  due 
largely  to  their  gaseous  products.  The  bacillus  butylicus  fur- 
nishes an  inverting  and  a  peptonizing  ferment. 

The  micrococci  urese  (urease)  are  the  most  common  factors 
in  the  ammoniacal  fermentation  of  urine.  Their  action  is 
favored  by  the  presence  of  mucus. 

Putrefying  ferments  are  both  aerobic  (outside  body)  and 
anaerobic  (intestines — alkaline).  They  act  mostly  on  proteins, 
the  anaerobic  producing  H  and  fatty  acids,  then  NH3,  H2S, 
C02,  amins,  amids,  and  phenol  compounds,  and  finally  peptons, 
toxalbumins,  and  ptomains. 

Nitrifying  ferments  are  oxidizing  agents,  converting  KH3 
and  albuminoids  into  nitrous  and  nitric  acids,  which,  in  contact 
with  the  mineral  matters  of  the  soil  or  of  surface  waters,  form 
nitrites  and  nitrates,  essential  plant-foods.  The  rootlet  nod- 
ules of  beans,  pease,  clover,  and  other  leguminosae  contain 
myriads  of  these  bacteria,  which  enable  the  plants  to  utilize 
the  nitrogenous  matters  in  air  and  soil  and  even  to  fix  the 
free  N  of  the  atmosphere. 

The  pathogenic  organisms  of  specific  infections  excite  dis- 
eases mainly  by  means  of  the  toxins  which  they  generate  while 
rioting  in  the  fluids  of  the  body. 

Finely  divided  Pt,  Pd,  and  Ir  behave  in  some  respects  as  do 
enzymes.  They  are  capable  of  inverting  cane-sugar. 


QUESTIONS   ON  THE   CARBON   COMPOUNDS. 

1.  What  is  the  present-day  significance  of  the  term  organic? 

2.  Distinguish  between  a  hydrocarbon  and  a  carbohydrate. 

3.  How  prove  that  a  substance  is  organic? 

4.  How  prove  that  a  substance  is  nitrogenous? 

5.  Mention  five  petroleum  derivatives. 

6.  Name  three  essential  oils  isomeric  with  turpentine. 

7.  Why  is  burning  acetylene  more  luminous  than  methane? 

8.  Of  what  is  benzene  the  source? 

9.  Distinguish   chemically   between   an   essential    oil,   a   resin,   an 
oleoresin,  a  balsam,  and  a  gum. 

10.  What  are  artificial  fruit  flavors? 

11.  Write  equation  for  alcoholic  fermentation  of  glucose. 

12.  How  can  you  change  the  taste  of  tannin  from  bitter  to  sweet? 

13.  Write    graphic    formulas    for    phenol,    benzaldehyd,    benzene, 
butane,  salicylic  acid. 

14.  Show  by  formulas  the  relations  between  the  three  classes  of 
carbohydrates. 

15.  How   distinguish  by   chemic  tests  between  dextrose,  maltose, 
and  lactose? 


QUESTIONS.  255 

16.  Write  equation  for  "fire-damp"  explosion. 

17.  Explain  drying  of  paints  with  turpentine. 

18.  Describe  and  explain  the  tests  for  the  purity  of  CHClj,. 

19.  What  special   precautions   should  be  employed  in  using  ether 
as  an  anesthetic? 

20.  Why  are  baking  soda  and  ammonia  suitable  applications  for 
insect-  and  nettle-  stings? 

21.  Which  contains  most  olein,  lard  or  lallow? 

22.  What  causes  the  curd  when  we  use  soap  in  hard  water? 

23.  Mention  three  carbohydrates  of  animal  origin. 

24.  Why  is  a  mixture  of  dextrose  and  levulose  called  invert-sugar? 

25.  What  is  the  difference  between  a  ptomain,  leucomain,  and  a 
toxin  ? 

26.  What  is  likely  to  be  formed  if  we  prescribe  chloral  hydrate 
with  alkalies? 

27.  What  official  ointment  contains  elaidin? 

28.  What  dangers  in  anesthesia  from  badly  kept  chloroform? 

29.  How  are  ink-stains  removed  by  oxalic  acid? 

30.  Explain  spontaneous  combustion  of  greasy  rags. 

31.  Give  formula  of  paraformaldehyd. 

32.  Give  formula  of  acid  radical  (acetyl)  of  acetic  acid;  formula  of 
basic  radical. 

33.  Does  gallic  acid  tan  leather,  and  why? 

34.  What  makes  garden  rhubarb  ("pie-plant")  so  sour? 

35.  Is  ether-vapor  lighter  or  heavier  than  air? 

36.  Write  equation  for  reaction  between  Seidlitz  powders. 

37.  How  does  clover  restore  the  fertility  of  fields? 

38.  Explain  the  action  of  hair-dyes  containing  lead  salts. 

39.  How  distinguish  the  action  of  organized  from  unorganized  fer- 
ments ? 

40.  How  does  lemonade  render  the  urine  less  acid? 

41.  What  organic  acid  keeps  the  urine  acid? 

42.  Why  are  the  foulest-smelling  stools  alkaline? 

43.  Why  is  air  needed  to  change  weak  alcoholic  liquors  to  vinegar? 

44.  Why   are   alkaloids   often   preferred  in   medicine   to   the   crude 
drugs  and  their  preparations? 

45.  How  is  tea  an  antidote  for  alkaloidal  poisons  generally? 

46.  Why  do  animal  substances  putrefy  readily? 

47.  How  does  butter  become  rancid? 

48.  Why  is  sweat  sour? 

49.  What  causes  the  very  bad  smell  of  some  persons'  feet? 

50.  How  do  sweet  foods  often  cause  a  "sour  stomach"? 

51.  Why  does  new  cider  cause  diarrhea? 

52.  Why  is  "rot-gut"  whisky  so  injurious? 

53.  How  is  bread  raised  with  yeast? 

54.  How  do  alcoholics  save  the  tissues  in  fever? 

55.  How  are  wines  ripened? 

56.  How  is  glycerin  produced  in  the  body? 

57.  Explain  the  color-changes  of  litmus  with  acids  and  bases. 

58.  How  test  for  the  presence  of  carbolic  acid  in  creasote? 

59.  Distinguish  between  an  amid,  an  amin,  an  anilid,  and  an  amido- 
acid. 

60.  Why  should  boiling  water  not  be  used  in  making  a  mustard 
plaster? 


ANALYSIS. 


QUALITATIVE  ANALYSIS. 

GENERAL  DIRECTIONS  AND  REMARKS. 

Do  NOT  test  an  aqueous  solution  for  compounds  insoluble 
in  water.  Only  distilled  water  should  be  used. 

As  little  of  the  reagents  as  practicable  should  be  employed 
— seldom  above  1  gm.  or  1  c.c.,  except  in  the  case  of  highly 
diluted  reagents,  such  as  H2S  solution. 

In  dissolving  metals  use  as  little  acid  as  possible,  then 
evaporate  nearly  to  dryness  in  a  porcelain  dish,  and  take  up 
residue  with  water  before  applying  tests. 

In  separating  a  mixture  of  salts  be  sure  to  add  excess  of 
precipitating  reagent,  so  as  to  throw  down  all  of  the  salt  tested 
for. 

Pour  off  supernatant  liquid  before  trying  solubility  of  a 
sediment;  in  many  cases  it  is  best  also  to  wash  the  sediment 
with  water.  If  there  is  much  sediment,  take  only  a  small  por- 
tion for  each  test  of  solubility. 

If  a  powdered  substance  is  insoluble  in  water,  try  dilute, 
then  strong  HC1,  then  HN03  or  aqua  regia.  All  these  failing, 
make  soluble  by  fusing  with  a  mixture  of  carbonates  of  Na  and 
K;  the  insoluble  sulphates  of  alkaline  earths  are  thus  converted 
into  carbonates,  soluble  in  HC1  after  filtering  away  the  soluble 
alkaline  sulphates  that  are  formed.  Insoluble  salts  may  also  be 
boiled  with  strong  NaHO;  then  dilute,  filter,  and  test  filtrate 
with  usual  reagents. 

An  acid  reaction  to  litmus  does  not  necessarily  indicate  a 
free  acid  or  an  acid  salt,  since  many  normal  salts,  especially 
sulphates,  are  acid  in  reaction. 

Decrepitation  on  heating  is  due  to  expansion  of  water  in 
the  crystals.  Deflagration,  or  the  vivid  combustion  of  charcoal 
when  some  substances  are  heated  with  the  blow-pipe  on  it,  is 
caused  by  certain  oxidizing  agents,  particularly  chlorates  and 
nitrates. 

(256) 


QUALITATIVE  ANALYSIS. 


257 


23  4 

Fig.  35.— Apparatus  for  Solution.     (Rockwood.) 

1,  Test-tubes  in  wooden  supports.  2,  Beakers.  3,  Iron  stand  with  adjustable 
rings  for  supporting  objects  while  they  are  heated.  On  one  of  the  rings  is  a  sand-bath. 
H,  Flasks. 


Fig.  36.— Apparatus  for  Evaporation.     (Rockwood.) 
1,  An  extemporized  steam-hath— a  beaker  of  water  on  which  a  dish  can  be  heated. 


-         -'    •  >c»i\ci   Ul   «„„„.   „„     ,,..,v..  «  viio.i    >;au    uo    iiCJlwu. 

^,  A  copper  steam-bath  with  tubes  supplying  water  and  allowing  the  excess  to  escane 
thus  maintaining  a  constant  level.  The  funnel  above  excludes  dust  3  A  sulphuric 
±l3!ff^1±^L*?"rtedwl*  air-r"Unp-  Iu  front  are  evaporating  dishes  of 


porcelain,  platinum,  and  glass. 


17 


258 


ANALYSIS. 


Fig.  37.— Apparatus  for  Filtration.     (Kockwood.) 

1,  A  funnel  fitted  to  a  filtering  flask  which  is  connected  with  a  pump  for  the  pro- 
duction of  a  vacuum,  and  consequently  an  increase  in  the  rapidity  of  the  filtration. 
2,  A  support  holding  funnels  for  filtration.  3,  Washing  bottles.  In  front  are  packages 
of  filter-paper  with  two  plaited  filters. 


2  3 

Fig.  38. — Apparatus  for  Fusion.     (Rockwood.) 

1,  Porcelain  crucible.  2,  Hessian  or  clay  crucibles,  with  a  pipe-stem  triangle  lean- 
ing against  middle  one.  3.  A  graphite  crucible.  4,  A  platinum  crucible  with  cover. 
In  front  are  forceps  and  crucible  tongs. 


FINDING  THE  METAL.  259 

Eeduction  on  charcoal  is  usually  best  accomplished  by 
heating  with  the  blow-pipe  the  finely-powdered  substance, 
placed  in  a  hollow  in  the  charcoal  after  mixing  with  twice  its 
weight  of  dry  KCN  and  Na2C03.  Incrustations  around  the 
heated  spot  are  due  to  oxids. 

Sublime  and  volatile  substances,  such  as  As,  are  easily 
recognized  by  heating  in  a  bent  dry  glass  tube  open  at  both 
ends,  and  noting  the  mirror,  or  deposit  of  drops  or  crystals 
recondensed  in  the  cooler  part  of  the  tube. 

To  separate  the  metals  from  each  other,  we  employ  a  small 
number  of  group  reagents,  each  of  which  throws  down  a  certain 
group  of  metals — more  quickly  when  heated.  HC1  is  the  gen- 
eral reagent  of  the  first  analytic  group  (Ag,  Pb,  Hg1),  throw- 
ing down  an  insoluble  chlorid  of  each  or  all  of  these  metals. 
H2S  (preferably  the  gas,  added  to  solution  previously  acidu- 
lated with  HC1)  ppts.  as  sulphids  the  metals  of  the  extensive 
second  group,  which  is  further  subdivided  according  as  the 
ppt.  is  soluble  or  insoluble  in  NH4HS  (made  by  saturating 
NH4HO  with  H2S).  This  latter  solution  (after  supersaturating 
with  NH4HO)  ppts.  the  members  of  the  third  group.  (NH4)2- 
C03  (1  part  of  commercial  salt  dissolved  in  a  mixture  of  4  parts 
of  H20  and  1  part  of  NH4HO)  ppts.  the  alkaline  earths,  which 
constitute  the  fourth  group.  An  aqueous  10-per-cent.  solution 
of  Na2HP04  is  the  reagent  for  Mg,  or  the  fifth  "group."  The 
metals  of  the  alkalies  are  left  in  the  final  filtrate.  These  re- 
agents must  be  used  only  in  the  order  mentioned,  and  must 
generally  be  added  in  excess  in  order  to  ppt.  the  total  quantity 
of  metal  or  metals  in  each  group,  which  is  separated  by  filtra- 
tion before  passing  to  the  next  group. 


FINDING  THE  METAL. 

GROUP  I  (Pb,  Ag,  Hgi). 
( Group  reagent  =  HC1 . ) 

{PbCl2  —soluble  in  boiling  water. 
AgCl — insoluble  in  H2O  ;  soluble  in  dilute  NH4HO  (1  to  10). 
Hg2Cl2— insoluble  in  H2O  and  turned  black  by  NH4HO. 

Separation. 

1.  Pb  dissolved  out  with  boiling  H2O  and  repptd.  from  filtrate  with  dilute 

H2S04. 

2.  Ag  dissolved  from  first  residue  with  dilute  NH4HO  and  repptd.  with  HNO3. 

3.  Hg,  if  present,  left  as  a  black  residue  from  filtration  of  Ag. 


2GO 


ANALYSIS. 


Blackish  ppt. 


GROUP  II  (Hg«,  Bi,  Cu,  Pb,  Cd,  Sb,  As,  Sn«-iv,  Pt,  Au). 
(Group  reagents  =  HC1  [a  few  drops]  and  H2S  [excess].) 

Division  I  (ppt.  insoluble  in  yellow  NH4HS).    • 
Yellow  ppt.  =  CdS. 

(  HgS  —  brownish  f  Yellow  =  Hg. 

yellow,    then  I   Blue  =  Cu  ( decolorized  by 

black.  O  (original)    |       KCN). 

Bi2S3.  +  KHO      -{  Bi— insoluble  in 

CuS.  excess  of  KHO 

PbS.  Wn't  (yellow     oxid 

I  J  on  boiling). 

Pb  —  soluble  in 
excess  of  KHO. 

Division  II  (ppt.  soluble  in  yellow  NH4HS  on  digesting  in  an 
evaporating  dish). 

Orange  ppt.  =  Sb2S3. 
Brown  or  blackish  ppt. 


Yellow  ppt. 


First 
Division 


SnS.  O  -j-  HgCl2  on  boiling  gives  a  gray  ppt. 
PtS2.  O  +  KC1  4  C2H5HO  gives  a  yellow  ppt. 
Au2S3.  O  -j-  SnCl2  gives  a  purple  ppt. 
As2S3 — heated  with  KCN  and  Na2CO3  in  a  bent  glass  tube 

gives  a  black  metallic  mirror  above. 

SnS2  —  O  -f  KHO  gives  a  white  ppt.,  soluble  in  excess,  not 
t          repptd.  on  boiling. 

Separation. 

1.  Boiling  HNO3  dissolves  all  ppts.  except  HgS  (black  residue). 

2.  Dilute  H2SO4  throws  down  Pb  ( white )  from  above  solution. 

3.  Strong  NH4HO  throws  down  Bi  (white)  from  nitrate  of  No.  2. 

Filtrate  of  No.  3  blue  if  Cu  is  present. 
Yellow  =  Cd. 

4.  H2S  ppts.    -j   Black  =  Cu  (decolorized  and  kept  in  solution 


\ 


by  KCN  while  Cd  is  pptd.  with  H2S). 


r  i. 


Second 
Division 


Boiling 
ppts. 


HC1 


i 


2. 


Filtrate  may 
contain 


As — yellow  if  alone,  blackish  if  Au  or  Pt 
present ;  soluble  in  (NH4)2CO3,  repptd. 
by  HC1. 

f  Au  pptd.  by  Fe- 
Residue  from  As,    j       SO4. 
soluble  in  aqua  \   Pt  pptd.  from  fil- 
regia  tratebyKCl  + 

I.      C2H5HO. 

Separated  by  electrolysis  between  a 
piece  of  Pt  (Sb  forms  a  black  coat- 
ing) and  a  strip  of  Zn. 
j   Sn,  if  present,  is  deposited  as  a  loose, 
[      metallic  sediment. 


Au 
Pt 


GKOUP  III  (Fe,  Co,  Ni,  Cr,  Al,  Ce,  Mn,  Zn,  Ca3    [PO4]2). 

(Group  reagents  =  NH4C1,  NH4HO  [till  alkaline],  and  NH4HS.) 

Division  I  (ppt.  formed  by  NH4HO  turned  black  by  NH4HS). 

Black  color  bleached  by  HC1  =  Fe2(  HO  )6.      O  +  K6Fe2Cy12  (ferrous)  or  K4Fe- 
Cy6  (ferric)  gives  a  blue  ppt. 


FINDING  THE  METAL.  261 

f  CoS.  O  4-  KHO  gives  bluish  ppt.,  turning  pink  on 

Black  residue  from  HC1  \   ^.^  }^lm£ur 

ISib.  O-T-KHO  gives    green    ppt.,    unaltered  on 
boiling. 

Dii-ision  II  (ppt.  formed  by  NH4HO  unchanged  in  color  by  NH4HS). 
Green  ppt.  =  Cr2(HO)6 

C  A12(HO)B.  O-f  KHO  gives  a  white,  gelatinous  ppt.,  soluble 

in  excess,  repptd.  by  boiling  with  excess  of  NH4C1. 

White  ppt.    \  f  Ce  leaves  a  red  residue 

Ce(HO)       f  O  +  KHO  gives  a  white          on  evaporating  and 
/-.    (po  \    "       PPt-  insoluble  in  ex-  -I       heating. 

3        4      I      cess.  Ca3(PO4)2  is  soluble 

[      in  HC2H3O2. 

Division  III  (ppt.  with  NH4HO  instantly  soluble,  but  NH4HS 
gives  a  light-colored  ppt. ). 

Flesh-colored  ppk  =  MnS —  fused  on  Pt  foil  with  Na2CO3  and  KNO3  forms 

a  green  mass  of  K2MnO4. 
White,  gelatinous  ppt.  =  ZnS  —  moistened  with  a  drop  of  Co(NO3)2  and 

heated  on  charcoal  it  turns  green. 

Separation. 

1.  HC1  dissolves  all  the  group  ppts.  except  Co  and  Ni,  which  are  separated 

by  dissolving  in  aqua  regia,  then  adding  KHO  in  excess  ;  Ni  is  pptd., 
and  Co  is  obtained  from  filtrate  by  evaporation. 

2.  Evaporate  HC1  solution  nearly  to  dryness,  take  up  with  water,  boil  with 

excess  of  KHO,  and  filter,  saving  precipitate. 

3.  NH4C1  ppts.  Al  (white)  on  boiling  with  filtrate  of  No.  2  and  standing. 

4.  NH4HS  ppts.  Zn  (white)  from  filtrate  of  No.  3  on  standing. 

5.  Fuse  ppt.  from  No.  2  on  Pt  with  Na2CO3  and  KNO3  ;  a  green  mass  indi- 

cates Mn.  Treat  mass  with  boiling  water,  filter,  and  save  residue  for 
Fe  ;  ppt.  Mn  (white)  with  K4FeCy6  and  filter  again. 

6.  Acidulate  second  filtrate  from  No.  5  with  HC2H3O2  and  ppt.  Cr  (yellow) 

withPb(C2H3O2)2. 

7.  Dissolve  residue  from  No.  5  in  dilute  HC1,  and  ppt.   Fe  (blue)  with 

K4FeCy6. 

8.  When  phosphates  are  present,  boil  filtrate  from  Group  II  till  all  H2S  is 

expelled  ;  add  a  few  drops  of  HNO3  ;  heat  to  boiling  again  ;  add  NH4C1, 
NH4HO,  and  NH4HS  ;  and  filter,  reserving  this  filtrate,  containing 
phosphates,  for  the  fourth  arid  fifth  groups. 

GBOUP  IV  (Ba,  Ca,  Sr). 
(Group  reagents  =  NH4C1,  NH4HO,  NH4HS,  and  [NH4]2CO3.) 

f  BaCO3.  O  -f  K2CrO4  gives  a  yellow  ppt. 
White  ppt.    ^   CaCO3.  O  -f  ( NH4  )2C2O4  gives  a  white  ppt. 
[  SrCO3  —  crimson  flame. 

Separation. 

1.  Dissolve  group  ppt.  in  HC2H3O2. 

2.  K2CrO4  ppts.  Ba  (yellow);  yellow  color  of  filtrate  removed  by  repptg., 

washing  with  water,  and  again  dissolving. 

3.  Dilute  K2SO4  ppts.  Sr  (white)  on  standing,  from  filtrate  of  No.  2. 

4.  (NH4)2C2O4  ppts.  Ca  (white)  after  rendering  filtrate  of  No.  3  alkaline 

with  NH4HO. 


262  ANALYSIS. 

GROUP  V  (Mg). 

( Reagents  =  NH4C1,  NH4HO,  NH4HS,  [NH4]2CO3,  andNa2HPO4.) 
White  ppt.  =  NH4MgPO4  —  feathery  crystals  under  microscope. 

GKOUP  VI. 

Flame  Tests:  Na,  yellow  (shut  off  by  cobalt-blue  glass) ;  K  (and  NH4),  violet; 

Li,  carmine  red. 
Odor  Test:  Boiling  O  with  KHO  gives  odor  of  NH3  and  vapors,  turning  moist 

red  litmus-paper  blue. 

[  Na2HPO4  and  NaHO  ppt.  Li  (white). 

Precipitation      \  Sodium  cobaltic    nitrite    [Co2(NO2)6.6NaNO2]    ppts.    K 
(yellow)  in  presence  of  acetic  acid. 

1.  Na2HPO4  and  NaHO,  boiling  till  all  NH8  is  expelled,  ppts. 

Li2HPO4. 

2.  Sodium  cobaltic  nitrite  ppts.  K  from  nitrate  of  No.  1,  after 

acidulating  with  HC2H3O2. 
Separation     J   3'  Test  originai  solution  for  NH3  by  boiling  with  KHO.    The 
amount  of  gas  can  be  estimated  volumetrically  by  passing 
into  a  standardized  HC1  solution. 

4.  Na  is  tested  in  O  by  flame  test,  and  is  estimated  gravimet- 
rically  by  subtraction  of  all  other  ingredients  from  the 
total  solids. 


NOTES. 

HC1  may  ppt.  oxychlorids  (soluble  in  excess)  of  Sb  or  Bi  from 
solutions  of  certain  compounds  of  these  metals.  It  also  ppts.  silica  from 
soluble  silicates,  and  oxids  or  hydroxids  [Zn(HO)2,  for  instance]  pre- 
viously dissolved  in  alkaline  hydroxids. 

S  is  sometimes  pptd.  on  addition  of  H2S,  with  or  without  a  change 
in  color  (red-brown  ferric  compounds  become  green  ferrous),  owing  to 
the  deoxidizing  action  of  H2S,  the  H  becoming  oxidized  to  water,  while 
S  is  set  free. 

Dilute  H2SO4  ppts.  all  the  members  of  the  second  division  of  the 
second  group  from  solution  in  NH4HS.  Acids  added  to  yellow  ammonium 
sulphid  (polysulphid)  form  a  soluble  NH4  salt  and  ppt.  S  (white  and 
milky),  which  should  not  be  mistaken  for  the  members  of  the  arsenic 
division. 

The  third  group  reagents  ppt.  also  phosphates,  borates,  oxalates, 
and  silicates  of  Mg  and  alkaline  earths  from  their  solutions  in  weak 
acids. 

When  the  first  group  reagent  fails  to  yield  a  ppt.  add  H2S  to  the 
same  tube.  When  reagents  of  third  group  show  no  ppt.,  add  to  same 
fluid  (NH4)2C03  for  fourth  group,  and  Na2HP04  for  fifth  group. 


FINDING  THE  ACID.  263 

FINDING  THE  ACID,  OR  RADICAL. 

RESIDUES— PROBABILITIES. 

(If  a  liquid,  notice  reaction  to  litmus  and  evaporate  to  dryness, 
then  heat  to  redness.) 

No  Residue: 

Neutral:    water   (no  odor). 

Strongly  acid:   some  volatile  acid  (acetic,  hydrochloric,  nitric,  etc.). 
Residue: 
Strongly  acid: 

Fusible  by  heat:    non-volatile  mineral  acids  (phosphoric). 
Residue  chars  on  heating:    free  organic  acid   (tartaric,  citric,  etc.). 
Neutral  or  slightly  acid: 

Residue  volatile  with  fumes,  but  without  blackening:    salt  of  vola- 
tile metal   (NH4,  Hg,  Sb,  As). 
Residue  blackens   and  volatilizes  in  fumes:     organic   salt  of   some 

volatile  metal. 

Residue  changes  color  on  heating: 
Yellow  hot,  cooling  white  =  Zn. 
Deep-yellow  hot,  cooling  yellow  =  Pb. 
Yellowish  brown  hot,  cooling  pale  yellow  =  Sniv. 
Orange-yellow  hot,  cooling  lemon-yellow  =  Bi. 
Red  hot,  cooling  reddish  brown  =  Fe  or  Ce. 
Permanent  brownish  black  =  Mn. 

Residue  white,  darkens  on  heating,  burns  and  leaves  black  or  gray- 
ish mass:    organic  salts  of  fixed  metals. 
Alkaline  residue  =  K,  Na,  Li. 

Non-alkaline  residue,  effervescing  with  HC2H3O2  —  Ba,  Sr,  Ca. 
Residue  that  takes  fire  and  continues  to  burn  after  removal  from 

flame  writh  dense,  white  fumes  —  hypophosphite. 
Strongly  alkaline:   leaving  fixed  white  alkaline  residue. 
Acidulate  some  of  original  with  HC1: 
Effervescence: 

Without  smell  =  carbonates  or  bicarbonates  of  K,  Na,  or  Li. 

O  +  HgCl2  gives  a  red  (carbonate)  or  white  (bicarbonate)  ppt. 
With  smell: 

Of  H2S  =  sulphid  of  alkali  or  alkaline  earth. 
Of  HCN  =  alkaline  cyanid. 
No  Effervescence.     Add  AgNO3  to  original: 
Brownish  black  =  hydroxid  of  alkali  or  alkaline  earth. 
Yellow  —  phosphate    "] 
White  =  borate  [   of  K  or  Na. 

J{ rick-red  =  arsenate  J 

PRELIMINARY  EXAMINATION  OF  SOLID  ACIDS  AND  SALTS. 

Step  I. — Heat  a  portion  of  the  powdered  substance  on  Pt  foil: 

Charring:    organic  acids  or  salts    (except  oxalates),  sugar    (reduces 

cupric  solution),  or  alkaloids  (odor  like  burning  hair). 
Ignition:   C,  S,  P,  and  all  organic  compounds. 
Decrepitation:   NaCl  and  other  salts  containing  H2O. 
Deflagration-:   chlorates,  nitrates,  iodates,  etc.,  on  charcoal. 
Irritating  vapors:   benzoic  acid. 


264  ANALYSIS. 

Fusible:   most  salts  of  alkalies  and  some  of  alkaline  earths. 
Infusible:    salts   of  earths  and  most  silicates  and   salts   of  alkaline 
earths  and  heavy  metals. 

Step  II. — Put  a  portion  in  tube,  cover  with  water,  and  render  barely 

acid  with  dilute  H2SO4: 
Red  vapors:  nitrites. 
Effervescence: 

Without  odor:     carbonate — evolved  gas  renders  lime-water   milky. 

Effervescence  also  takes  place  cold. 
With  odor: 

Sulphid:    like  sewer-gas. 

Sulphite:     like  burning  sulphur    (S02). 

Cyanid:     odor  of  HCN. 

Hypochlorite:    chlorin  odor,  greenish-yellow  fumes. 

Step  III. — Add  another  drop  of  H2S04,  and  warm  again.     These  effects 

often  occur  in  the  second  step: 
Characteristic  odors: 

Vinegar  =  acetate:    odor  of  acetic  ether  on  adding  alcohol. 
Sulphur  dioxid  =  hyposulphite:    with  deposit  of  S. 
Carbolic  acid  =  carbolate :    a  few  drops  of  Fe2Cl6  erives  a  violet  color. 
Valerian  =  valerianate :     Cu(C2H3O2)2  added  to  distillate  forms  a 
slow,  oily  ppt.,  gradually  solidifying  into  greenish-blue  crystals. 
Benzoic  acid  =  benzoate:    light-red  ppt.  with  Fe2Cl6  in  presence  of 

enough  NH4OH  to  render  slightly  alkaline. 
HCN: 

With  deposit  of  S  —  sulphocyanid :    blood-red  color  with  Fe2Cl6. 
Crystalline  deposit,  often  bluish: 

Ferrocyanid:    ferric  salts  give  a  blue  ppt. 
Ferricyanid:    ferrous  salts  give  a  blue  ppt. 

Step  IV. — Put  a  little  0  (original  solid)  in  a  dry  tube,  cover  with  strong 
H2S04  drop  by  drop,  and  warm  gently,  keeping  the  acid  below 
b.p.: 
White  fumes: 

Chlorid:     odor  of  HC1;   AgN03  gives  curdy  white  ppt.,   soluble  in 

NH4OH. 
Nitrate:     faintly-reddish  vapors,  turning  more  red  on   addition  of 

FeS04. 

Fluorid:    fumes  etch  glass. 

Benzoate:    very  irritating  vapors  (see  test  above). 
Succinate:    Fe2Cl6  gives  a  brownish-red  ppt. 

Sulphocarbolate :    same  tests  as  for  carbolates;  also  after  fusion  with 
KN03  and  redissolving  in  dilute  HC1  it  gives  sulphate  reaction 
with  BaCl2. 
Ammonium  compounds:    dense,  white  fumes  on  holding  near  mouth 

of  tube  a  glass  rod  dipped  in  HC1. 
Colored  fumes: 

Violet  vapors  of  I: 

lodid:    blue  with  starch  paste  and  Cl  water. 

lodates:    blue  color  with  starch  paste  on  adding  KI  and  tartaric 

acid. 
Brown  vapors  of  Br: 

Bromid:    orange  color  when  mixed  with  starch  paste  and  a  few 

drops  of  Cl  water. 
Bromate:    deflagrates  on  charcoal,  leaving  corresponding  bromid. 


FINDING  THE  ACID.  265 

Greenish-yellow   gas   =   chlorates:     explodes   readily;    spontaneous 
ignition    of   tissue-paper   dipped   in   benzin   when   dropped   into 
beaker  containing  chlorate  and  H2SO4. 
Simple  cliaiif/e  in  color: 

Chromates:    orange,  then  green. 

Dichromates :    turn  green  at  once. 

Oxids  of  heavy  metals:    darken  by  reduction  to  metallic  state. 
Effervescence  on  wiinnuuj,  with  no  odor  or  change  in  color: 

Formate:    gives  oft  CO  only,  burns  with  bluish-lavender  flame. 

Oxalate:     gives   off   both   CO   and   CO2,  thus   rendering    lime-water 

milky. 
Effervescence  on  warming,  with  darkening  in  color: 

Tartrate:    rapid  charring  and  smell  of  burnt  sugar. 

Lactate:  not  so  dark;  odor  of  sour  milk;  odor  of  aldehyd  on  boil- 
ing with  KJMn.Os. 

Citrate:    slow  darkening,  with  slight  odor  of  burnt  sugar. 

Oleate:    charring,  with  sharp,  disagreeable  odor  of  acrolein. 
Darkening  in  color  without  .any  very  marked  effervescence: 

Tannate:  solution  forms  black  ink  with  FeS04;  no  ppt.  with  gelatin 
(unless  gum  is  present). 

Gallate:  solution  forms  a  black  ink  with  FeS04;  immediate  brown- 
ish ppt.  with  gelatin. 

Pyrogallate:    solution  turns  blue  with  ferrous,  red  with  ferric  salts. 

Salicylate:    very  slow  darkening;  deep-violet  coloration  with  Fe2Cl6. 

Meconate:    red  color  with  Fe2Cl6,  not  discharged  by  HgCl2  or  dilute 

HC1. 
No  fumes: 

Silicate:    gelatinous  or  flaky  deposit. 

Borate:    scaly  crystals  with  pearly  luster,  best  seen  on  cooling. 
No  change  whatever: 

Sulphate:  hepar  test:  heat  with  a  little  Na.COg  on  charcoal  in  inner 
blow-pipe  flame  (reduction  to  sulphid)  ;  residue  placed  on  a 
clean  silver  coin  moistened  with  H20  leaves  a  black  stain. 

Phosphate:  solution  of  (NH4)2Mo04  in  HNO3  yields  a  yellow  ppt. 
insoluble  in  HNO3,  soluble  in  NH4OH. 

Phosphite:  heated  with  AgN03  yields  ppt.  of  metal  Ag;  same  re- 
action as  phosphate,  after  heating  with  HNO3. 

Arsenate:    boil  with  NaHO,  filter,  exactly  neutralize  filtrate  with 

dilute  HNO.,,  add  AgN03,  and  get  brick-red  ppt. 

,  Arsenite:     AgNO3  gives  canary-yellow  ppt.   of  AgoAsO3,   soluble  in 
excess  of  NH4OH  or  HNOS. 

Alkaline  oxids:  soluble  in  HC1  or  HNO3  without  effervescence: 
negative  findings  as  to  acid  radicals  except  that  of  solvent. 

DETECTION  OF  ACIDS  AND  ACIDULOUS  RADICALS  IN  SOLUTION.1 

AgN03,  Reagent: 
Neutral  or  acid  (HNOJ  reaction: 
White  ppt.: 

HC1  or  chlorids:  curdy  ppt.  insoluble  in  boiling  HN03,  but  in- 
stantly soluble  in  dilute  NH4HO  (1  to  20);  hypochlorites  give 
same  reaction,  with  odor  of  Cl. 

1  Find  metal  or  metals  present  before  testing  for  acid  radicals ;  then 
test  for  the  salts  of  the  metal  known  to  be  soluble.  If  O  (evaporated) 
does  not  char  on  heating  with  HyS04,  no  organic  acids  or  salts  except 
H2C2O4  can  be  present. 


266  ANALYSIS. 

HBr  or  bromids:  dirty-white  ppt.,  insoluble  in  HNO3,  slowly  sol- 
uble in  strong  NH4HO  (not  in  dilute). 

HCN  or  cyanids:  curdy  ppt.  with  bitter-almond  odor,  sparingly 
soluble  in  NH4OH,  in  strong  boiling  HNO3,  but  not  in  dilute 
HNO3;  does  not  blacken  on  exposure  to  light,  as  chlorid  and 
bromid  do. 

Ferrocyanids :  gelatinous  ppt.,  dissolved  by  NH4OH;  ferric  solu- 
tions give  a  dark-blue  ppt.,  insoluble  in  HC1. 

Sulphocyanid:    turns  blood-red  on  adding  a  ferric  solution. 
Light  yellow  =  HI  or  alkaline  iodids:    ppt.  does  not  dissolve  in  hot 

HN03  and  is  practically  insoluble  in  NH4OH. 
Black  ppt.: 

H2S  or  sulphids:  sewer-gas  odor  often  noticeable  on  treating  with 
a  mineral  acid. 

HCHO2  and  formates:    metallic  Ag  separates  on  boiling. 

HC3H503  and  lactates:  dark  ppt.  on  boiling,  leaving  a  blue  liquid 
on  subsidence. 

Neutral  reaction: 
White  ppt.: 

H2SO3  and  sulphites:    turns  black  on  heating. 

H2C03    and    carbonates:      effervesce    with    cold    acids    generally, 

evolved  gas  turning  lime-water  milky. 
H3BO3  and  berates:    ppt.  soluble  in  HNO3  or  NH4OH;  green  flame 

on  igniting  with  alcohol  in  case  of  solid  acid. 
H2C204  and  oxalates:    soluble  in  NH4OH  and  in  hot  concentrated 

HN03;  acid  decolorizes  K2Mn2Os  solution. 
H2C4H4O6  and  tartrates:    turns  black  on  boiling;   silver  mirror  on 

warming  mixture  after  adding  just  enough  NH4OH  to  dissolve 

ppt. 
H3C6H5OT  and  citrates:    no  mirror  of  Ag  on  boiling;  both  this  and 

that  above  char  on  heating  in  solid  form. 
H3PO3  and  phosphites:    turn  black,  from  metallic  Ag. 
Hypophosphites :     soluble   in   excess:     turns   yellow,   brown,   and 

black    (reduction).     0  heated  with  HgCl2  yields  calomel,  then 

black  Hg. 

Meta-  and  pyro-  phosphates:    soluble  in  HN03  and  in  NH4OH. 
Thiosulphates :     white    ppt.    on    adding   excess    of   reagent — soon 

turns  yellow,  brown,  and  black  (Ag2S),  more  quickly  on  heating. 
Yellow  ppt.: 

H3P04  and  phosphates:    lemon-yellow  ppt.  soluble  in  HNO3  and  in 

NH4OH.    O  gives  with  solution  of  (NH4)2Mo04  in  HN03  a  yellow 

ppt.,  which  is  insoluble  in  HNO3,  but  soluble  in  NH4OH. 
H3AsO3  and  arsenites:     canary-yellow  ppt.  with  argent-ammonium 

nitrate,  soluble  in  excess  of  NH4OH  or  HNO3. 
Reddish  ppt.: 

H3AsO4  and  arsenates:    brick-red  ppt. 

H2Cr04  and  chromates:     dark-red  ppt.,   soluble  in   HN03  and  in 

NH4OH. 

Ferricyanids :  orange  ppt.  O  +  ferrous  solutions  gives  a  dark- 
blue  ppt.,  insoluble  in  acids. 

BaCl2,  Reagent: 
Neutral  or  alkaline  reaction: 
White  ppt.: 

H2SO4  and  sulphates:  insoluble  in  boiling  H2O  and  in  boiling 
HNO3;  strong  HaS04  chars  organic  substances. 


FINDING  THE  ACID.  267 

H2SO3  and  sulphites:    white  ppt.  produced  on  boiling  with  BaCl2 

and  Cl  water  or  HN03   (forms  sulphate). 
H2CO3  and  carbonates:    soluble  in  HC1  with  effervescence. 
H3P04  and  phosphates:    soluble  in  acetic  and  all  stronger  acids. 
tUC204  and  oxalates:    insoluble  in  HC2H302;  soluble  in  HC1,  HNO3, 

or  NH4C1. 
H3B03  and  borates:    soluble  in  excess  of  water,  in  HC1,  or  NH,C1. 

Turmeric  paper  turns  brown-red  on  drying,  after  dipping  in  hot 

solution  of  acid  (borates  must  first  be  rendered  just  acid  with 

HC1). 

H2C4H4O8  and  tartrates:    soluble  in  NH4  salts  or  in  HC1. 
H3AsO4  and  arsenates   (see  special  tests  for  As). 
Thiosulphates:     soluble  in   excess  of  water,  and  decomposed  by 

HC1  with  pptn.  of  S. 
Yellow  ppt.: 
H2Cr04  and  chromates  :    ppt.  soluble  in  HNO3,  insoluble  in  HC2H302. 


Reagent: 

Neutral  or  sliyhtly  acid: 
Yellowish  ppt.: 

H3PO4  and  phosphates:    light-yellow,  gelatinous  ppt.  in  presence 

of  NaC2H3O2.     Avoid  excess  of  Fe2Cle. 
H2C2O4  and  oxalates:    soluble  in  HC1  or  HNO3. 
H3BO3  and  borates:    turmeric  test  (see  under  BaCl2). 
H;jAsO4  and  arsenates  (see  special  tests). 

H2CO3  and  carbonates:    yellowish-brown  Fe2(HO)6;  CO2  escapes. 
Reddish  ppt.: 

HC7H5O2  and   benzoates:     flesh-colored  or  reddish-white  ppt.    (in 

slightly  alkaline  medium),  soluble  in  acids,  including  benzoic. 
HC2H302  and  acetates  :    reddish-brown  coloration,  pptg.  on  boiling  ; 

color  discharged  both  by  HC1  and  HgCl2. 
Sulphocyanids  :    blood-red  coloration,  not  destroyed  by  dilute  HC1, 

but  disappears  on  adding  HgCl2. 
Pyrogallic  acid   (C6H6O3)  :    red  solution. 
H2C7H2O7  and  meconates:    red  color,  not  discharged  by  HgCl2  nor 

by  dilute  HC1. 
Black  ppt.: 

H2S  and  sulphids:    disgusting  characteristic  odor  evolved  on  treat- 

ing with  HC1. 
HC14H9O9  and  tannates:    bluish  black  or  greenish  black,  dissolved 

in  excess  of  tannin,  decolorized  by  HC1  or  H2C2O4. 
Blue  or  violet  ppt.: 

Ferrocyanids  :    dark  Prussian  blue,  decomposed  by  alkalies   (red- 

dish brown),  insoluble  in  acids   (restore  blue  color  after  treat- 

ing with  alkalies). 
Thiosulphates    ("Hyposulphites")  :     reddish   violet,  gradually   dis- 

appearing by  spontaneous  reduction. 
CaHBOH   and   carbolates:     permanent   reddish-violet   color.     O    + 

excess  of  Br  water  gives  white  ppt.   (tribromphenol). 
HC7H5O3  and  salicylates:    deep-violet  coloration. 
Brownish:    ferricyanids  :    brownish  coloration,  changed  to  blue  ppt. 

on  adding  reducing  agents  (H2SO3  or  SnCl2). 

CaCl2,  Reagent: 
Neutral  or  alkaline: 
White  ppt.: 

H2SO4  and  sulphates:    ppt.  best  secured  by  adding  a  half-volume 


268  ANALYSIS. 

of  alcohol  and  shaking;  ppt.  dissolves  readily  in  dilute  HN03 
or  HC1,  as  also  in  saturated  solution  of  KN03. 

Na,S2O3,  or  NH4  salts. 

H2SO3  and  sulphites:    O  +  strong  acid  yields  odor  of  S02. 

H2CO3  and  carbonates:  soluble  in  NH4C1,  and  in  acids  with  effer- 
vescence. 

H3PO4  and  phosphates:    soluble  in  acetic  and  all  stronger  acids. 

H3BO3  and  berates:  soluble  in  HC2H3O2  and  stronger  acids,  and  in 
slightly  alkaline  solutions  (NH4OH)  or  in  NH4C1. 

H3AsO4  and  arsenates  (see  special  tests  for  As). 

H2C2O4  and  oxalates:  soluble  in  HC1  or  HNO3,  insoluble  in 
HC2H3O2. 

H2C4H4O6  and  tartrates:  soluble  in  KHO,  redeposited  on  boiling; 
also  dissolved  by  HC2H3O2. 

H3CBH507  and  citrates:  white  ppt.  on  boiling,  soluble  in  NH4C1 
(not  in  KHO)  and  redeposited  on  boiling. 

HgCL,  Reagent: 
Neutral,  alkaline,  or  acid: 
White  ppt.: 

Bicarbonates  of  K,  Na,  and  Li:    effervesce  with  acids. 
Hypophosphites :    slightly  acidulated  with  HC1,  give  a  white  ppt. 

of  calomel,  turning  dark  on  heating. 

Reddish-brown  ppt.  =  carbonates  of  K,  Na,  and  Li;  effervesce  with 
acids. 

FeS04,  Reagent: 
Neutral  reaction: 
Dark-brown  ppt.: 

HN02  and  nitrites:    best  shown  as  a  dark  ring  by  contact  method 

— disappears  on  heating. 
HNO3  and  nitrates :    in  presence  of  H2S04,  dark  coloration  -as  with 

nitrites. 

White  ppt.  =  f errocyanids :    changes  quickly  to  blue. 
Blue  ppt.  —  f erricyanids :    ppt.  insoluble  in  acids;    deposits  dirty- 
green  Fe(HO)2  when  boiled  with  KHO. 

DETECTION  AND   SEPARATION  OF  MIXED   SALTS. 

If  the  student  will  bear  in  mind  the  reactions  for  the 
separate  salts,  he  will  have  little  difficulty  in  deducing  methods 
for  differentiating  mixtures  of  salts.  The  following  notes  will 
serve  as  illustrations: — 

1.  To  Separate  Chlorids,  Bromids,  and  lodids. — All  three  give  a 
light-colored  ppt.  with  AgN03.     This  ppt.,  washed  on  a  filter  and  per- 
colated with  dilute  NH4HO    (1  to  20),  will  show  in  the  percolate  any 
chlorid  by  repptn.  with  HN03.    The  remaining  deposit  on  the  filter-paper 
may  be  treated  with  strong  NH4HO,  which  dissolves  out  any  bromid 
(repptd.  with  HN03),  leaving  Agl  as  a  light-yellow  residue.     A  mere 
cloud  on  adding  the  acid  should  be  disregarded. 

2.  To  Detect  Bromids  in  Presence  of  lodids. — A  blue  color,  pro- 
duced on  adding  very  little  starch  solution  and  a  drop  or  two  of  Cl 
water,  shows  an  iodid.     On  adding  more  Cl  water  the  blue  color  is  dis- 
charged, when,  if  any  bromid  is  present,  it  is  revealed  by  a  yellow  color 
on  snaking  with  chloroform. 


SEPARATION  OF  SALTS.  269 

3.  To  Separate  Chlorids  from  Chlorates. — All  the  chlorid  is  pptd. 
with  excess  of  AgNO8  and  filtered  out.     The  filtrate  is  acidulated  with 
H2SO4  and  a  fragment  or  two  of  zinc  dropped  in,  when  if  a  chlorate  is 
present  it  will  be  reduced  to  chlorid  and  give  a  second  ppt.  on  adding 
AgNO,. 

4.  To  Separate  Sulphids,  Sulphites,  and  Sulphates. — Pour  solution 
on  excess  of  CdCO3,  digest  at  a  gentle  heat,  filter,  and  dissolve  uncom- 
bined  carbonate  in  HC2H3O2.    A  yellow  residue  on  the  paper  indicates  a 
sulphid.     The  filtrate  may  contain  sulphite  and  sulphate,  to   separate 
which  add  BaCl2,  filter  out  ppt.,  and  boil  with  a  little  HC1,  which  dis- 
solves out  BaSO:!  with  evolution  of  SO2  and  leaves  the  insoluble  BaSO4. 

5.  To   Separate   Chlorids,   lodids,   and  Bromids   from   Nitrates. — 
Ag2SO4  ppts.  the  halogens  and  leaves  the  nitrate  in  solution. 

6.  To  Separate  Chlorids  from  Cyanids. — Both  are  pptd.  by  acidulat- 
ing slightly  with  HN03  and  adding  excess  of  AgNO3.    The  cyanid  in  the 
ppt.,  after  washing  thoroughly  with  boiling  water  by  decantation,  is  dis- 
solved in  boiling  HNO3,  leaving  the  insoluble  chlorid.     HC1  is  added  to 
the    acid    solution,    throwing    down    a    white    ppt. — cyanid    changed    to 
chlorid. 

7.  To  Separate  Ferrocyanids  from  Ferricyanids. — The  ferrocyanid 
is  pptd.  with  excess  of  Fe2Clc,  after  acidulating  with  HC1.     The  super- 
natant brownish  liquid  also  gives  a  blue  ppt.  when  heated  with  a  little 
zinc  amalgam  (reduction)  if  ferricyanid  is  present. 

8.  To   Detect    Cyanids   in   Presence    of    Ferrocyanids   and    Ferri- 
cyanids.— The  latter  two   salts  are  pptd.  by  acidulating  slightly  with 
HNO3  and  warming  gently  with  ferric  and  ferrous  sulphates.     When  a 
blue  color  is  produced  in  some  of  the  supernatant  liquid  by  adding  excess 
of  KHO  and  then  acidulating  with  HC1,  a  cyanid  is  also  present. 

9.  To  Detect   a  Phosphate  in  Presence   of  Iron. — Dissolve  in   as 
little  HC1  as  possible;   add  some  H3C6H5O7  and  then  excess  of  NH4HO. 
From  this  solution,  when  cold,  magnesia  mixture  (1  part  each  of  NH4C1, 
NH4OH,  and  MgSO4  in  8  parts  of  water)   ppts.  white  crystals  of  NH4- 
MgP04. 

10.  To  Detect  a  Phosphate  in  Presence  of  Alkaline  Earths  (Mg 
or  Mn). — Dissolve  in  water  with  the  aid  of  as  little  HN03  as  possible, 
then  add  excess  of  NH4C2H,02  to  remove  any  excess  of  HNO3 ;  on  adding 
a  drop  or  two  of  Fe2Cl6  and  warming,  a  white  ppt.  of  Fe2(P04)2  is  formed. 

11.  To  Detect  Carbolic  in  Presence  of  Salicylic  Acid.— Add  1  m. 
each  of  saturated  solution  of  KHCO3,  and  anilin,  and  5  m.  of  solution 
of  chlorinated  lime,  when  a  deep  blue  is  produced  if  carbolic  acid  is 
present. 

12.  To  Separate  Oxalates,  Tartrates,  and  Citrates. — Make  slightly 
alkaline  with  NH4OH,  add  CaCl,,  allow  to  stand  for  ten  minutes,  and 
filter.     Filtrate  may  contain  citrate;   on  boiling  gives  slow,  white  ppt. 
on  sides  of  tube.     The  ppt.  may  contain  oxalate  and  tartrate:    acetic 
acid  dissolves  the  latter,  not  the  former.     The  tartrate  filtrate  gives  a 
white  ppt.  on  adding  NH4OH  to  render  slightly  alkaline,  and  on  further 
addition  of  AgNO3  and  boiling  yields  a  silver  mirror. 


PYROLOGY. 

An  ordinary  gas-,  candle-,  or  spirit-  flame  consists  of  three 
parts,  namely:  an  inner  dark  nucleus,  a  middle  luminous  cone 
or  mantle,  and  an  outer  bluish  sublumjnous  mantle.  The  first 


£70  ANALYSIS. 

portion  is  composed  of  a  mixture  of  unoxidized  gases;  the  sec- 
ond of  partially  oxidized  gases  (especially  C2H4  and  CH4),  the 
excess  of  C  in  solid  particles  reflecting  the  light  from  all  points 
and  thus  making  this  stratum  the  most  luminous;  in  the  third, 
or  outer  part,  which  is  most  exposed  to  the  0  of  the  atmos- 
phere, combustion  is  nearly  complete,  hence  the  flame  is  only 
feebly  luminous. 

The  Bunsen  flame  is  hotter  and  less  luminous  than  others, 
because  air  is  mixed  throughout  the  gases  instead  of  combining 
merely  on  the  surface,  as  in  ordinary  combustion.  The  hottest 


Fig.  39.— Bunsen  Flame. 

part  of  the  Bunsen  flame  is  the  bright  spot  at  the  apex  of  the 
zone  of  fusion  between  its  two  mantles  (4000°  F.);  hence  sub- 
stances to  be  fused  should  be  held  at  this  point.  H  burning  in 
0  furnishes  34,462  thermal  units;  C  in  0,  8080  units. 

Experiment. — Close  the  Bunsen  jet  at  the  bottom,  and  by  means 
of  a  small  glass  tube  prove  that  the  nucleus  of  the  flame  consists  of 
unburned  and  combustible  gases. 

The  blow-pipe  is  an  instrument  much  used  in  metallurgy 
and  analysis.  It  consists  of  a  metal  tube  with  a  narrow  nozzle, 
through  which  a  continuous  current  of  flame  can  be  passed  into 


PYROLOGY. 


271 


the  Bunsen  flame.  The  blow-pipe  flame  has  two  parts:  an 
inner  bluish  reducing,  and  an  outer  yellowish  oxidizing;  the  tip 
of  the  inner  cone  is  best  for  reduction.  Blowing  across  the 
flame  with  the  blow-pipe  lengthens  and  narrows  the  flame, 
thereby  increasing  the  sphere  of  combustion  and  the  degree  of 
heat,  and  concentrating  the  latter  within  narrower  limits. 

In  pyrology,  or  analysis  by  fire,  there  are  two  general 


Fig.  40.— Oxidizing  Blow-pipe  Flame  (Light  Blue). 

processes:  oxidation  and  deoxidation  (reduction).  For  oxidiz- 
ing purposes  the  flame  is  lowered  and  the  blow-pipe  pushed  into 
it  with  a  fair  current,  in  order  to  secure  free  admixture  with 
0.  The  substance  to  be  oxidized  is  held  in  the  tip  of  the  outer 
mantle  a  little  beyond  the  apex  of  the  luminous  cone.  For  re- 
ducing powders  to  the  metallic  state,  a  stronger  flame  and  a 


Fig.  41.— Reducing  Blow-pipe  Flame  (Yellow). 


weaker  current  are  employed;  the  blow-pipe  is  held  just  on 
the  border  of  the  flame,  the  substance  to  be  deoxidized  just 
within  the  luminous  apex:  i.e.,  the  part  of  the  flame  deficient 
in  0.  For  analytic  purposes  the  powder  is  mixed  with  about 
twice  as  much  Na2C03,  and  the  mixture  is  placed  in  a  hollow 
on  a  piece  of  charcoal. 

Experiment. — Oxidize  powdered  zinc. 
Experiment. — Reduce  BiONO3  to  metallic  bismuth. 


272  ANALYSIS. 


BLOW-PIPE   ANALYSIS. 

I.  Heat  on  asbestos  or  charcoal  before  blow-pipe. 

No  residue  —  ordinary  alkaline  salts:    fuse  and  sink  into  charcoal. 
Residue: 

Shining  white:    Moisten,  when  cold,  with  a  drop  of  Co(N03)2  and 
use  blow-pipe  again. 

Blue  =  Al  or  borates,  phosphates  or  silicates. 

Green  =  Zn. 

Pale-rose  or  flesh  colored  =  Mg. 

Colored:    Use  borax  bead. 

II.  Mix  with  twice  as  much  Na2C03,  and  heat  on  charcoal  in  reducing 

flame. 
Metallic  globules  or  powdered  mass: 

With  surrounding  incrustation  of  oxid: 
Yellow : 

Bi:    brittle  bead,  with  pink  tinge,  easily  fusible. 
Pb:    soft,  gray-white,  malleable;  marks  paper;  border  of  white 

carbonate. 

Sn:    white  bead,  very  oxidizable  and  fusible. 
White: 

Sb:    gray,  very  brittle,  readily  oxidized  and  volatilized   (white 
fumes)  ;  bead  skips  about  when  dropped,  leaving  a  white  trail. 
No  surrounding  incrustation: 

Ag:    clear,  white  malleable  bead;  does  not  oxidize  readily. 

Cu:    red,  tough,  malleable;  colors  flame  green. 

Fe:    reddish  magnetic  powder  (Fe3O4). 

Co:    light-  or  dark-  blue  mass,  according  to  amount. 

Ni:    violet  when  hot,  cooling  yellowish  brown. 

Mn:    green  mass  of  manganates  on  fusing  on  Pt  with  Na2C03 

and  KNO3. 

Cr:    yellow  mass  when  treated  like  Mn. 
Au:    bright-yellow  bead. 
Pt:    gray,  infusible  powder 
Only  incrustation  (metals  volatilize): 
White  =  As:    garlicky  smell. 

Yellow,  cooling  white  =  Zn:    may  be  greenish-white  mass  in  center. 
Reddish-brown  —  Cd. 
2Vo  globules  or  incrustation  =  Hg. 


VOLATILIZATION   TESTS. 

Mix  powdered  substance  with  a  little  charcoal  and  Na.,CO3,  place 
in  a  small  dry  test-tube,  and  heat,  watching  for  shiny  metallic  mirror 
or  sublimate  on  cooler  part  of  tube. 

Mercury:    minute  gray  globules. 

Arsenic:    gray-black  sublimate. 

Antimony:    similar  to  As,  but  lighter-colored. 

Sulphur:    yellow  sublimate. 

Ammonium  compounds:  NH3  given  off — recognized  by  odor  and 
action  on  moist  litmus-paper. 

Water  and  hydroxids:    steam. 


QUANTITATIVE  ANALYSIS.  273 


BORAX-BEAD    TESTS. 

On  heating  sufficiently  borax  loses  its  water  of  crystalliza- 
tion, fusing  into  a  glassy  substance  called  a  bead.  Borax  beads 
have  great  avidity  for  oxids,  and  with  the  blow-pipe  give  char- 
acteristic colors  in  the  oxidizing  and  reducing  flames  for  cer- 
tain metals,  as  shown  by  the  following  short  table: — 

METAL.  OXIDIZING  FLAME.  REDUCING  FLAME. 

Co  Blue.  Blue. 

Cr  Green.  Green. 

Cu  Green,  cooling  blue.  Red   (cold). 

Fe  Red,  cooling  yellowish.  Bottle-green. 

Mn  Amethyst.  Colorless. 

Ni  Red-brown,  cooling  yellow.  Red-brown,  cooling  yellow. 

FLAME   TESTS. 

Dip  loop  of  Pt  wire  in  HC1  (to  form  more  volatile  chlorid),  then 
catch  up  a  little  of  powder  or  concentrated  solution  and  hold  in  outer, 
colorless  flame  near  base.  The  following  metals  each  give  a  character- 
istic color  to  the  flame:  — 

Violet  =  K:  look  through  blue  glass  to  shut  out  yellow  colors; 
NH4  compounds  and  organic  matter  also  give  a  faint-violet  color. 

Yellow  =  Na:    color  intercepted  by  blue  glass. 

Reddish  yellow  =  Ca. 

Greenish  yellow  —  Ba  or  Mo. 

Green  —  Cu  or  boric  or  phosphoric  acid. 

Blue  =  Pb,  As,  Sb,  Bi,  CuCl2. 

Crimson  =  Li  (not  pptd.  from  solutions  by  NH4  compounds)  or  Sr 
(pptd.  from  solution  by  [NH4]2CO3  in  presence  of  NH4OH  and  NH4C1). 

QUANTITATIVE     ANALYSIS. 

Quantitative  determinations  are,  in  general,  either  gravi- 
metric or  volumetric.  Gravimetric  methods  consist  simply  in 
drying  and  weighing  the  various  ppts.  obtained  separately  as 
described  heretofore.  Precipitation  should  be  complete,  as 
shown  by  the  reagent  giving  no  further  ppt.  after  subsidence. 
Knowing  the  chemic  composition  of  the  ppt.,  the  amount  of 
each  element  in  it  and  the  weight  of  the  original  substance  in 
solution  are  readily  calculated  (see  "Stoechiometry").  The 
amount  of  substance  taken  to  be  analyzed,  if  in  the  solid  state, 
should  rarely  exceed  a  gram. 

All  the  ppt.  (usually  best  obtained  in  a  beaker,  avoiding 
excess  of  reagent)  is  collected  by  filtration  on  a  small  circle  of 
filter-paper  (Swedish  No.  2  is  best),  is  well  washed  with  dis- 
tilled water,  and  then  dried  by  placing  filter  and  contents  in  a 
drying  oven  at  100°  C.  The  dry  powder,  if  inorganic,  is  then 
transferred  from  the  paper  to  a  tared  crucible,  the  folded  paper 


274  ANALYSIS. 

(containing  particles  of  ppt.)  is  incinerated  on  the  lid  of  the 
crucible  over  the  flame,  and  the  ash  is  removed  to  the  crucible, 
which  is  now  heated  until  all  moisture  is  expelled.  After  cool- 
ing in  a  desiccator  (a  closed  vessel  containing  a  dish  of  H2S04), 
the  crucible  and  its  contents  are  weighed,  and  the  weight  of 
the  crucible  alone  and  of  the  filter-ash  (previously  determined 
by  weighing  others,  or  stated  on  each  package)  deducted.  Or- 
ganic ppts.  generally  and  some  inorganic,  like  K2PtCl6,  are  col- 
lected on  a  previously  dried  and  weighed  filter,  well  washed, 
dried  at  100°,  then  weighed;  the  weighing  each  time  is  best 
done  between  two  watch-crystals  held  together  by  clamps. 

It  should  be  borne  in  mind  that  ignition  often  changes  the 
character  of  a  ppt.;  thus,  oxalates  become  carbonates;  hydrox- 
ids,  oxids;  and  phosphates,  pyrophosphates.  The  water  of 
crystallization  is  estimated  by  heating  a  gram  or  so  of  the 
salt  in  the  air-bath  at  from  120°  to  300°  until  no  further  loss 
in  weight  takes  place.  The  carbonic  acid  of  carbonates  is  gen- 
erally determined  by  treating  with  dilute  HC1,  and  calculating 
the  loss  as  C02. 

In  the  wet  methods  of  quantitative  analysis  it  is  particu- 
larly necessary  to  throw  down  all  of  a  given  compound  by  add- 
ing the  reagent  drop  by  drop  to  the  solution,  with  shaking  or 
stirring  and  sometimes  warming,  until  no  further  ppt.  is  pro- 
duced. After  this  the  mixture  should  stand  for  a  few  minutes 
to  allow  complete  precipitation  to  take  place.  The  ppt.  on  the 
filter  should  be  well  washed,  as  a  rule,  by  means  of  a  jet  of 
distilled  water  from  the  wash-bottle,  saving  the  washings  with 
the  remainder  of  the  filtrate  for  the  next  reagent.  Cloudy 
washings  can  usually  be  prevented  by  allowing  the  deposit  on 
the  filter  to  drain  dry  before  washing.  Filtration  is  aided  by 
conducting  the  clear  supernatant  liquid  down  a  glass  rod  from 
the  lip  of  the  beaker  on  to  the  filter  before  washing  the  ppt.  out 
of  the  beaker. 

In  the  use  of  the  analytic  balance  and  weights  care  should 
be  taken  never  to  put  any  chemical  directly  on  the  pan,  but  in 
a  clean  tared  crucible  or  watch-crystal;  to  use  forceps,  not 
fingers,  for  lifting  weights;  to  keep  the  beam  off  the  knife- 
edges  when  making  any  transfer;  to  weigh  corrosive  substances 
in  stoppered  tubes;  and  to  keep  dust  out  of  the  instrument  as 
much  as  possible.  Careful  notes  should  be  taken  of  each  step 
and  a  systematic  record  kept  for  final  calculations  and  future 
reference. 

Experiment. — Weigh  out  1  gm,  of  BaCl2.2H2O,  dissolve  in  100  c.c.  of 
water,  ppt.  Ba  with  dilute  H2SO4,  dry  and  weigh  ppt.,  and  reckon  from 
this  weight  that  of  the  chlorid  first  taken. 


QUANTITATIVE  ANALYSIS.  275 

The  volumetric  method  is  very  rapid  and  convenient,  and 
consists  essentially  in  adding  to  a  substance  in  solution  from 
a  buret  (titration)  a  standard  solution  of  the  reagent  until  the 
reaction  is  just  completed,  as  shown  by  color-changes  in  the 
substance  tested  or  in  some  other  substance  added  as  an  indi- 
cator. Graduated  flasks  or  beakers  and  pipets  are  also  utilized 
in  this  method. 

Standard  solutions  are  either  normal  or  empiric:  that  is, 
arbitrary,  as  Fehling's  solution,  which  is  so  constituted  that  1 
c.c.  is  completely  reduced  by  5  mg.  of  dextrose. 

All  normal  solutions  are  chemically  equivalent  to  each 
other  in  equal  volumes.  They  are  prepared  by  dissolving  in  a 
liter  of  distilled  water  the  weight  in  grams  of  a  molecule  (gram- 
molecule)  of  the  substance  (including  water  of  crystallization) 
in  the  case  of  monovalent  substances  (monacid  or  monobasic); 
one-half  the  gram-molecule  in  the  case  of  substances  combin- 
ing in  the  divalent  role  [H2S04,  Na2C03,  Ca(HO)2];  and  one- 
third  the  gram-molecule  of  substances  whose  hydrogen  equiv- 
alence of  the  positive  and  the  negative  ions  is  3.  By  the  stand- 
ard or  titer  of  a  volumetric  test  solution  is  meant  its  strength 
per  liter  or  cubic  centimeter.  A  normal  solution  is  expressed 
briefly  as  N/x.  More  delicate  results  are  obtained  by  diluting 
normal  solutions  10  to  100  times,  the  resulting  solutions  being 
designated  as  N/10  (decinormal)  or  N/100  (centinormal). 

Volumetric  methods  are  of  three  general  types:  direct, 
indirect,  and  residue.  The  neutralization  of  an  acid  with  an 
alkali  is  an  example  of  the  first;  the  liberation  of  Cl  from 
HC1  by  boiling  with  Mn02  and  the  estimation  of  the  Cl  with 
KI  as  liberated  I  by  means  of  Na2S203  is  an  example  of  the 
second;  the  estimation  of  CaC03  by  difference  on  treating  with 
a  normal  acid  solution,  which  is  afterward  titrated  with  alkali 
to  determine  the  loss  of  acidity,  is  an  example  of  the  third 
class. 

The  chief  general  processes  included  under  volumetric 
titration  are  neutralization  (acidimetry  and  alkalimetry),  oxida- 
tion (dichromates,  permanganates),  reduction  (ferrous  salts, 
H2C204),  precipitation,  and  iodimetry  (estimation  of  I  with 
Na2S203). 

The  principal  color-changes  are  in  litmus  (from  red  to 
blue  for  neutralization  of  acids,  and  vice  versa),  phenol-phthal- 
ein  (1-per-cent.  solution  in  dilute  alcohol:  pink  with  alkalies, 
colorless  with  acids),  cochineal  or  rosolic  acid  (yellow  with  acids, 
violet  with  alkalies;  used  chiefly  for  NH3  and  JSTH4  compounds), 
methyl  orange  (0. 1-per-cent.  aqueous  solution:  yellow  with 
hydrates,  carbonates,  and  bicarbonates;  orange-red  with  acids), 


276  ANALYSIS. 

starch  solution  (blue  with  I),  K2Cr04  (red  color  with  Ag  salts), 
and  ferric  alum  (brown-red  with  KSCN"). 

A  few  drops  of  these  solutions  are  added  to  the  substance 
to  be  tested,  also  in  solution  in  a  beaker  or  flask.  K2Mn208 
gives  off  0,  and  is  decolorized  on  heating  with  organic  sub- 
stances in  an  acid  solution.  Cr03,  on-  reduction,  changes  from 
orange  to  green. 

The  basis  for  normal  acid  solutions  is  oxalic  acid,  which 
is  chosen  because  it  does  not  contain  a  variable  quantity  of 
non-crystalline  water,  as  is  the  case  with  the  common  mineral 
acids.  The  full  formula  of  crystallized  oxalic  acid  is  H2C204.- 
2H20;  hence  the  molecular  weight  is  125.7.  Being  dibasic, 
one-half  this  weight,  or  62.85  gm.  of  the  acid,  is  dissolved  in 
sufficient  distilled  water  at  15°  to  make  a  liter. 

The  basis  for  normal  alkali  solutions  is  Na2C03,  of  which 
52.92  gm.,  or  half  the  gram-molecule,  is  dissolved  in  water  and 
diluted  to  a  liter.  Other  normal  alkali  solutions  (KHO,  NaHO) 
are  obtained  by  dissolving  approximately  the  H  equivalence 
(one-half  or  the  full  molecular  weight  in  grams)  of  the  sub- 
stance in  about  1000  c.c.  of  water,  then  titrating  with  normal 
acid  and  diluting  with  water  until  10  c.c.  of  the  acid  solution 
is  exactly  neutralized  by  10  c.c.  of  the  alkali.  Other  normal 
acid  solutions  than  oxalic  are  standardized  by  means  of  a  nor- 
mal alkali  solution. 

In  titrating  carbonates  with  normal  acid,  the  alkaline  solu- 
tion should  be  boiled  toward  the  end  of  the  reaction  in  order 
to  drive  off  C02,  which  has  an  acid  reaction  on  litmus  and  phe- 
nol-phthalein,  but  not  on  methyl  orange.  Alkali  salts  of  the 
organic  acids  are  first  converted  into  carbonates  by  ignition 
before  titrating  with  acids. 

Acids  neutralize  bases  (including  oxids,  carbonates,  and 
organic  salts  after  ignition),  and  bases  neutralize  acids  or  acid 
salts  (such  as  KH2P04).  For  example: — 

39.96       36.37       58.37      17.96 
NaHO  +  HC1  =  NaCl  +  H20 

As  shown  by  the  molecular  weights  with  the  above  equa- 
tion, 1  c.c.  of  any  normal  solution  is  equivalent  to  1  c.c.  of  any 
other  for  which  it  is  a  test,  and  the  exact  weight  of  any  acid  or 
alkali  in  solution  is  readily  found  by  neutralizing  with  a  normal 
or  decinormal  alkali  or  acid,  and  multiplying  the  number  of  c.c. 
used  of  the  latter  by  the  weight  in  mg.  of  1  c.c.  of  a  normal 
solution  of  the  substance  tested.  The  following  table  of  com- 
mon neutralization  equivalents  in  grams  is  convenient  for  refer- 
ence:— 


QUANTITATIVE  ANALYSIS.  277 

ONE  C.C.  OF  NORMAL  ACID  is  ONE  C.C.  OF  NORMAL  ALKALI  is 
EQUIVALENT  TO  EQUIVALENT  TO 

Ammonia 0.01701  Acetic  acid 0.05986 

Ammonium  carb.  (U.S.  P.)  0.05226  Citric  acid 0.06983 

Lead  subacetate 0.13662  Hydrobromic  acid 0.08076 

Lithium  carbonate     ....  0.03693  Hydrochloric  acid 0.03637 

Potassium  bicarbonate  .    .    .0.09988  Hydriodic  acid 0.12753 

Potassium  carbonate  ....  0.06895  Hypophosphorous  acid  .    .    .  0.06588 

Potassium  hydroxid  ....  0.05599  Lactic  acid 0.08989 

Potassium  permang 0.03153  Nitric  acid 0.06289 

Pot.  sodium  tartrate  .    .    .    .0.14075  Oxalic  acid 0.06285 

Sodium  bicarbonate  ....  0.08385  Phosphoric  acid  (K2HPO4)  .  0.04890 

Sodium  borate 0.19046  "     (KH2PO4)  .  0.09780 

Sodium  carbonate 0.05292  Potassium  dichromate   .    .    .0.14689 

Sodium  hydroxid 0.03996  Sulphuric  acid 0.04891 

Strontium  lactate 0.13244  Tar taric  acid   .  ...    .0.07482 


The  pharmaceutic  practice  of  volumetric  work  is  to  weigh 
out  such  an  amount  of  the  substance  for  analysis  that  the  num- 
ber of  c.c.  of  the  normal  solution  used  will  express  the  per- 
centage. Thus,  3.64  gm.  of  United  States  Pharmacopeia  dilute 
HC1  containing  10  per  cent,  of  the  anhydrous  acid  is  exactly 
neutralized  by  10  c.c.  of  normal  alkali. 

Alkaloids  can  be  estimated  volumetrically  by  dissolving  in 
a  measured  amount  of  N/20  HC1  and  determining  the  excess  of 
acid  over  that  which  combines  with  the  alkaloid,  by  means  of 
N/2o  NaHO,  using  phenol-phthalein  as  an  indicator.  Each  c.c. 
of  the  N/20  acid  is  equivalent  to  the  following  gram  factors  of 
alkaloids: — 


Aconitin    0.0323       Coniin    0.0062 

Atropin  0.0144       Morphin    0.0142 

Brucin   0.0197       Nicotin    0.0040 

Cinchonin   0.0147       Quinin   0.0162 

Cocain  0.0151       Spartein    0.0028 

Codein  0.0149       Strychnin 0.0167 


Mayer's  solution,  or  the  decinormal  potassium  mercuric 
iodid  solution,  contains  39.2  gm.  of  this  salt  per  liter,  and  is 
made  by  dissolving  13.546  gm.  of  HgCl2  in  600  c.c.  water  and 
49.8  gm.  KI  in  100  c.c.  water,  mixing  the  two  solutions  and 
diluting  up  to  1000  c.c.  This  solution  is  used  in  estimating 
some  of  the  alkaloids,  which  should  be  distinctly  acidified  (not 
with  HCoH^O;,)  before  running  in  the  reagent.  The  end  of  the 
reaction  is  shown  when  the  reagent  produces  a  ppt.  with  a  few 
drops  of  clear  filtrate;  an  excess  should  be  avoided.  The  ppts. 
formed  by  Mayer's  reagent  are  compounds  of  the  base  with  one 


278  ANALYSIS. 

or  more  molecules  of  HI  and  HgI2.  The  following  equivalents 
have  been  determined  experimentally  for  each  c.c.  of  the  deci- 
normal  solution: — 

Aconitin    0.0269  Morphin    0.0200 

Atropin  0.0097  Narcotin  0.0213 

Berberin 0.0425  Nicotin    0.0040 

Brucin    0.0197  Physostigmin     0.0137 

Cinchonin 0.0102  Quinidin    0.0120 

Coniin    0.0125  Quinin  0.0108 

Emetin    0.0189  Strychnin    0.0167 

Hyoscyamin     0.0069  Veratrin    0.0296 

Oxidimetry  is  accomplished  by  means  of  potassium  per- 
manganate, K2Mn208  (315.34),  which  gives  off  5  atoms  of  0 
in  the  presence  of  H2S04  and  organic  matter: — 

K2Mn208  +  3H2S04  ==  K2S04  +  2MnS04  +  50  +  3H20 

A  normal  oxidizing  solution  is  one  which  will  liberate  as 
much  0  per  liter  as  is  equivalent  to  1  gram-atom  of  H,  namely: 
1/2  gram-atom,  or  8  gm.  of  0,  since  it  takes  2  of  H  to  combine 
with  1  of  0.  A  normal  solution  of  K2Mn208  therefore  con- 
tains V10  its  molecular  weight  (1/2  -=-  5),  or  31.534  gm.  per 
liter.  It  is  standardized  by  means  of  normal  (or  decinormal) 
oxalic-acid  solution,  equal  volumes  of  which  completely  decol- 
orize the  permanganate  solution.  The  equivalence  of  normal 
K2Mn208  for  different  substances  is  obtained  by  studying  the 
equations  representing  their  reactions.  For  example:  KN02 
-j-  0  =  KN03.  Nitrites  take  up  1  atom  of  0,  equivalent  to 
2  liters  of  N/±  K2Mn208  .  • .  the  equivalent  factor  of: — 

TT-vro    39.03+14.01+31.92 84.96  _  n  fMo^o 

JS.1MJ2—  2x1000  -  2000  —   U-U4^40 

The  decinormal  equivalent  is  0.004248.  In  estimating  Fe  and 
its  compounds  with  K2Mn208,  ferric  compounds  must  first  be 
reduced  to  ferrous  by  heating  in  a  flask  with  nascent  H  (Zn 
+  H2S04). 

The  following  are  the  most  important  equivalences  of  1 
c.c.  of  decinormal  K2Mn208: — 

Barium  dioxid 0.008441       Hydrogen  dioxid    0.001696 

Ethyl  nitrite   0.003743  Hypophosphorous  acid  .  .  0.001647 

Ferrous  carbonate   0.011573       Oxalic  acid  (cryst.) 0.006285 

Ferrous  oxid   0.007195       Oxygen    0.000798 

Ferrous  sulphate   0.015170  Potassium  hypophosphite.  0.002598 

Ferrous  sulphate  (cryst.)  .   0.027742  Sodium  hypophosphite  . .  0.002646 

lodimetry  depends  on  the  reaction  between  I  and  Na2- 

S,0,:- 

21  +  2Na2S203  =  2NaI  +  Na2S406 


SPECIAL  METHODS.  279 

Normal  solutions  of  both  these  substances  are  used  with 
starch  solution  (1  gm.  of  starch  in  200  c.c.  of  boiling  water)  as 
an  indicator  of  uncombined  I.  The  thiosulphate  is  also  em- 
ployed for  the  volumetric  determination  of  Cl  and  of  ferric 
salts  through  the  agency  of  KI,  free  I  being  liberated.  Deci- 
normal  I  solution  is  made  by  dissolving  12.653  gm.  of  I  in  a 
solution  of  18  gm.  of  KI  in  300  c.c.  of  H20  and  diluting  to  a 
liter.  Sodium  thiosulphate  contains  5  molecules  of  water  of 
crystallization;  hence  its  normal  solution  is  made  to  contain 
247.64  gm.  of  the  salt  per  liter. 

Decinormal  AgN03  solution  (16.955  gm.  per  liter)  is  used 
for  the  direct  estimation  of  haloid  salts  and  acids.  Normal 
K2Cr04  is  used  as  an  indicator,  forming  permanent  red  chro- 
mate  of  silver  as  soon  as  all  the  chlorid,  bromid,  and  iodid  has 
been  pptd. 

Copper  is  generally  estimated  volumetrically  by  a  standard 
solution  of  KCN,  made  by  dissolving  60  gm.  of  KCN  in  a  liter 
of  water,  the  solution  to  be  kept  in  a  dark  place  in  a  glass- 
stoppered  bottle.  Then  weigh  out  0.25  gm.  of  pure  Cu  foil  or 
wire,  place  in  a  beaker,  and  add  10  c.c.  each  of  HN03  and  H20, 
and  boil  till  all  the  Cu  is  dissolved  and  brown  fumes  cease  to 
appear.  Transfer  the  solution  and  beaker  washings  to  a  100 
c.c.  flask,  dilute  to  the  mark,  and  shake  thoroughly.  Take  half 
of  this  in  a  beaker,  add  slight  excess  of  NH4OH  and  run  in  the 
KCN  solution  until  the  blue  color  is  changed  to  a  faint  pink. 
Eepeat  the  standardizing  process  with  the  other  half  of  the  Cu 
solution,  and  take  the  average  of  the  two  findings.  Compute 
the  equivalence  factor  by  dividing  0.125  by  the  number  of  c.c. 
of  KCN  used  to  decolorize  the  Cu  solution.  Thus,  if  it  takes 
20  c.c.  of  KCN  to  remove  the  blue  color,  then  the  factor  is: — 

0.125 -=-20  =  0.0062 


SPECIAL  METHODS  AND  APPARATUS. 

ARSENIC   TESTS. 

If  dissolved  in  stomach-contents,  separate  from  colloids  by 
dialysis,  and  destroy  all  organic  matters  by  boiling  for  some 
hours  with  addition  of  HN03,  and  filtering.  The  chemicals 
and  dishes  used  must  first  be  proved  free  of  arsenic  by  blank 
tests. 

1.  Ignite  on  charcoal  with  blow-pipe  and  note  garlicky  odor. 

2.  Heat  a   small   quantity  in   a   reduction   tube   with   Na2CO3   and 
KCNj   observe  dark  metallic  mirror  in  upper  part  of  tube,  due  to  As. 


280 


ANALYSIS. 


On  breaking  off  lower  end  of  tube  and  heating  again,  we  get  a  crystal- 
line mirror  of  As2O3. 

3.  Fleitmann's  Test. — Boil  a  small  piece  of  Al  with  KHO: — 

Al,  +  2KHO  +  2H2O  =  K2A1204  +  3H2 

In  presence  of  As  HsAs  is  formed,  reducing  AgNO3  (white  filter-paper 
dipped  in  strong  solution  and  held  over  mouth  of  tube)  to  black,  shining, 
metallic  Ag.  Sb  does  not  react  to  this  test  at  all. 

4.  Keinsch's    Test.  —  The    arsenic    solution    acidulated    with    one- 
seventh  as  much  HC1  deposits  a  blue-gray  film  of  As  (or  Sb,  Hg,  or  Bi) 
on  Cu  foil  with  the  aid  of  heat.    Wash  foil  in  water,  dry  with  filter-paper, 
and  heat  in  wide,  dry  test-tube.     Note  crystalline  deposit  in  upper  part 
of  tube.     Break  tube  and  examine  crystals  of  As.Os  under  microscope. 
They  are  octahedral — rhombic  prisms  if  cooled  rapidly.    Blank  test:    the 
Cu  and  acid  must  show  no  stain  on  prolonged  boiling  with   distilled 
water. 


Fig.  42. — Apparatus  for  Detection  of  Minute  Amount  of  Arsenic. 


5.  Marsh's  Test. — Prepare  nascent  H  from  pure  Zn  and  dilute 
H2SO,;  after  a  few  minutes  ignite  and  show  that  no  stain  is  produced 
by  the  flame  on  a  white  porcelain  surface.  Then  add  suspected  solution. 
If  As  is  present,  the  color  of  the  flame  changes  to  a  light  blue  (As203 
fumes)  characteristic  of  H3As,  and  a  dark  metallic  stain  is  left  on  a 
white  porcelain  surface  by  touching  it  to  the  flame.  This  stain  may  be 
either  metallic  As  or  Sb.  To  distinguish  between  the  two  (As  is  soluble 
in  NaCIO  solution)  dissolve  the  spot  in  a  drop  of  HN03,  evaporate  gently 
(As  is  volatile),  and  apply  a  drop  of  a  strong  solution  of  AgN03,  which 
gives  with  As  a  brick-red  mark  due  to  Ag3AsO4;  the  stain  exposed  to 
H2S  turns  lemon-yellow.  The  tube  through  which  the  H3As  passes,  when 
heated  to  a  dull-red  heat,  shows  a  mirror,  in  the  cooler  part,  of  metallic 
As.  Extinguish  the  flame  and  dip  delivery  tube  into  AgN03;  on  running 
NH4HO  over  the  latter  fluid  a  yellow  ring  appears  at  the  junction  of  the 
two  fluids.  Marsh's  is  the  most  delicate  test  known  for  As  and  its  com- 
pounds, showing,  it  is  said,  as  small  a  proportion  as  1  part  in  200,000,000. 
Unfortunately  it  is  inconclusive  in  the  presence  of  organic  matter,  which 
can,  however,  be  destroyed  by  oxidizing  with  HN03  or  with  KC103  and 
HC1. 


PLATE   II. 


s 


;/  r'-^ 


•U  '* 


Fig.  3 


fin.  <i.  Fig.  .7 

INORGANIC   POISONS. 


MICROCHEMIC  TESTS.  281 

MERCURY. 

Galvanic  Test. — Place  on  a  Cu  coin  a  drop  of  suspected  solution, 
acidulate  with  HC1,  and  touch  coin  at  this  spot  with  a  knife-blade.  Hg 
is  deposited  as  a  silvery  film  of  amalgam. 

COPPER. 

A  knife-blade  or  other  piece  of  bright  metal  dipped  into  an  acid- 
ulated solution  shows  a  red  deposit  of  metallic  Cu. 

Ammonia  added  to  solutions  containing  Cu  gives  a  blue  color  when 
enough  has  been  added  to  neutralize  any  acid  present. 

MAGNESIUM. 

Compounds  are  soluble  in  water  or  dilute  HC1.  (NH4)2CO3  does 
not  ppt.  if  NH4C1  has  been  added  first,  but  on  treating  also  with  Na2HPO4 
there  falls  a  feathery,  white  ppt. 

HYDROCYANIC   ACID. 

Liebig's  Test. — Place  a  portion  of  the  liquid  in  a  porcelain  capsule; 
add  a  few  drops  of  a  dilute  solution  of  NaHO  and  a  few  drops  of  solu- 
tion of  yellow  NH4HS.  Evaporate  to  dryness  on  water-bath;  then  add 
a  little  water  and  acidulate  with  HC1.  Finally  add  2  or  3  drops  of  solu- 
tion of  Fe2Cl6.  A  fine  red  color  proves  presence  of  HCN.  This  is  the 
most  delicate  of  all  the  tests  for  prussic  acid,  giving  a  distinct  reaction 
with  a  solution  of  1  to  4,000,000. 

PHOSPHORUS. 

Simon's  Test. — To  detect  minute  amounts  of  phosphorus  in  cases 
of  poisoning  render  the  matter  to  be  examined  fluid  by  the  addition  of 
water,  slightly  acidulate  with  H2S04,  and  place  in  a  flask  which  is  con- 
nected with  a  bent  glass  tube  leading  to  a  Liebig  condenser.  Place  the 
apparatus  in  the  dark  and  heat  the  flask,  raising  the  temperature  grad- 
ually to  the  b.p.  If  P  be  present,  a  luminous  ring  is  seen  where  the  glass 
tube  leading  from  the  flask  enters  the  condenser.  H3P03  or  small  globules 
of  P  may  be  found  in  the  fluid  collected  in  a  glass  vessel.  Vapors  of 
ether  or  essential  oils  diminish  or  prevent  the  luminosity  of  P  vapors. 

MICROCHEMIC   TESTS. 

These  are  very  delicate  and  attractive.  The  solution  tested 
should  seldom  be  above  0.01  per  cent,  in  strength,  and  a  small 
drop  of  this  and  of  the  reagent  is  sufficient.  It  is  often  well 
to  mix  the  solutions  warm  and  allow  them  to  cool  slowly  on  a 
slide.  A  polarizing  apparatus  and  a  goniometer  add  to  the 
interest  of  the  work. 

Ammonium. — On  adding  NaHO,  Na2HPO4,  and  MgSO4,  character- 
istic rhombic,  feathery  crystals  of  NH4MgPO4  are  formed. 

Arsenic. — As.03,  when  heated  in  a  narrow  tube  with  access  of  air, 
forms  in  the  cooler  part  a  sublimate  of  characteristic  colorless  octahedra, 
having  a  somewhat  triangular  outline.  (Fig.  4,  Plate  II.) 

Atropin. — A  dilute  solution  of  sulphate  yields  with  picric  acid  a 
copious  light-yellow  deposit,  which,  after  stirring,  soon  becomes  crystal- 


282  ANALYSIS. 

line,  and  appears  under  the  object-glass  as  aggregations  of  rhombic, 
transparent  plates.  (Fig.  5,  Plate  III.) 

Barium. — Ammonium  fluosilicate  ppts.  Ba  compounds  from  slightly 
acid  solutions  as  BaSiF6,  which  occurs  in  needles  and  rods. 

Calcium. — The  addition  of  a  soluble  sulphate  to  a  Ca  solution  ppts. 
colorless,  acicular  crystals,  often  arranged  in  radiate  masses  or  sheaves. 
Alcohol-vapors  render  the  reaction  more  sensitive. 

Corrosive  Sublimate. — A  very  small  quantity  heated  in  a  reduction- 
tube  volatilizes  unchanged  and  recondenses  as  feathery  or  snow-flake 
crystals  which  turn  red  on  sliding  a  drop  of  KI  under  the  cover-glass. 
(Fig.  1,  Plate  II.) 

Homatropin,  0.005  gm.,  dissolved  in  10  c.c.  of  boiling  acidulated 
(HC1)  water,  yields  with  5-per-cent.  AuCl3  on  cooling  large,  short  prisms, 
with  pointed  ends. 

Hydrocyanic  Acid. — Place  dilute  solution  of  acid  in  a  watch-glass, 
and  over  this  invert  another  glass  holding  to  its  surface  a  small  drop  of 
AgN03  solution.  The  acid  vapor  (driven  off  more  rapidly  by  warmth 
of  hand)  forms  a  white  film  of  AgCN,  which  appears  under  the  micro- 
scope as  very  small,  irregular,  prismatic  crystals  (vapors  of  Cl,  Br,  and 
I  yield  amorphous  deposits).  (Fig.  1,  Plate  III.) 

Hyoscyin  and  hyoscyamin  yield  with  AuCl3  long,  flat  needles  or 
irregular  plates,  respectively. 

Lead. — A  very  small  quantity  (Yam  grain)  in  solution  yields  with 
KI  a  yellow  ppt.,  which,  after  heating  to  boiling,  separates  on  cooling 
in  golden-yellow  six-sided  plates.  (Fig.  5,  Plate  II.) 

Lithium. — Na2HPO4  added  to  a  hot  neutral  solution  of  a  Li  salt 
causes  rectangular  crystals  of  Li2HPO4  to  separate. 

Magnesium. — Add  NH4C1,  heat  to  boiling,  then  add  a  wTarm  solu- 
tion of  Na,,HPO4  rendered  alkaline  with  NH4OH,  and  note  fern-like 
crystals  of  NH4MgPO4. 

Morphin. — One  one-hundredth  grain  of  salt  dissolved  in  1  m.  of 
H,O  yields  with  a  small  drop  of  KI,  on  stirring  and  standing,  a  white, 
crystalline  ppt.  consisting  of  radiate  bundles  of  fine  needles.  (Fig.  2, 
Plate  III.) 

Oxalic  Acid. — CaCl2  yields  octahedra,  small  and  colorless;  micro- 
scopic appearance  like  back  of  square  envelope.  ZnC2O4  is  similar  in 
structure.  (Fig.  3,  Plate  II.) 

Potassium. — Neutral  or  slightly  acid  solutions  evaporated  slowly 
after  adding  PtCl4,  exhibit  highly-refractive,  yellow  octahedra  of  K,PtClc. 
Alcohol  makes  the  test  more  sensitive. 

Quinin. — Stellar  groups  of  needles  quickly  appear  on  adding  0.5  c.c. 
of  5-per-cent.  K2CrO4  to  5  c.c.  of  saturated  aqueous  solution  of  sulphate. 

Sodium. — Acetate  of  uranyl  causes,  in  concentrated  Na  solutions, 
the  formation  of  tetrahedra  and  allied  forms  of  NaaH!O2,UO;!(C2H,O2)2. 

Strontium. — Chromates  ppt.  SrCr04  in  presence  of  NaC,H3O2:  yel- 
low rods,  spheres,  and  dumb-bells. 

Strychnin. — One  one-hundredth  grain  or  less  dissolved  in  1  m.  of 
H2O  and  treated  with  KCNS,  yields  a  white,  crystalline  ppt.,  consisting 
of  long,  radiating  prisms  and  club-shaped  forms.  (Fig.  3,  Plate  III.) 

(Fig.  "Z,  Plate  II  =  tartar  emetic.    Fig.  4,  Plate  III  =  aconitin.) 

NITROMETRY. 

The  nitrometer  is  an  instrument  consisting  of  two  upright 
glass  tubes  (one  open  above,  the  other  graduated  and  provided 
with  a  stop-cock)  connected  below  with  rubber  tubing.  It  is 


PLATE   III. 


if"    "I  X 


Fig.  3 


o 


FJtf. 


ORGANIC   POISONS. 


PHARMACEUTIC  ASSAYS. 


283 


used  especially  for  the  determination  of  the  strength  of  spirit 
of  nitrous  ether  and  amyl  nitrite,  from  the  volume  of  NO  that 
collects  in  the  closed  tube. 

Estimation  of  Ethyl  Nitrite.  —  According  to  the  United  States 
Pharmacopeia,  if  5  c.c.  of  recently  prepared  spirit  of  nitrous  ether  be 
introduced  into  a  nitrometer  and  followed  by  10  c.c.  of  KI  and  then  10 
c.c.  of  H2SO4,  the  volume  of  NO  generated  at  25°  C.  should  not  be  less 
than  55  c.c.  (corresponding  to  4  per  cent,  of  pure  ethyl  nitrite).  The 
instrument  is  commonly  filled  with  a  strong  common-salt  solution, 
which  does  not  absorb  NO.  To  take  the  reading  the  surface  of  the  liquid 
in  the  two  tubes  should  be  at  a  level  with  each  other:  — 

C2H5NO2  +  KI  +  H2S04  =  C2H5HO  +  I  +  KHSO4  +  NO 


Fig.  43.— Nitrometer. 


PHARMACEUTIC   ASSAYS. 

The  pharmaceutic  assay  of  organic  drugs  is  accomplished 
with  the  aid  of  extraction  apparatus  (Soxhlet  tube  for  hot  ex- 
traction) and  various  solvents,  especially  ether,  alcohol,  and 
chloroform,  or  with  Prollius's  fluid  (1  c.c.  of  stronger  NH4OH, 
2.5  c.c.  of  alcohol,  and  32.5  c.c.  of  ether).  The  active  principle 
is  commonly  extracted  by  macerating  10  gm.  of  the  finely  pow- 
dered substance  in  100  c.c.  of  the  solvent  for  twenty-four  hours, 
at  the  end  of  which  time  half  the  clear  liquid  is  decanted  and 
evaporated  until  the  ether  is  removed.  The  residual  liquid  is 
treated  with  0.5  c.c.  of  dilute  H2S04  and  10  c.c.  of  H20,  and 
filtered  into  a  separating  funnel,  washing  with  about  5  c.c.  more 
of  water.  The  resinous  and  coloring  matters  in  the  separator 
mixture  are  removed  by  shaking  with  two  or  three  portions  of 
ether  (10  c.c.  each  time),  after  which  the  remaining  aqueous 
solution  is  rendered  alkaline  with  NaHO  and  shaken  in  the 


284  ANALYSIS. 

funnel  with  1  volume  of  chloroform  and  3  volumes  of  ether, 
repeated  twice.  The  three  ethereal  solutions  are  evaporated 
to  dryness  in  a  tared  beaker,  then  weighed,  and  dissolved  in 
very  dilute  acid  and  tested  volumetrically.  When  very  little 
alkaloid  is  present  in  a  crude  drug,  alcohol  (0.820)  is  an  efficient 
solvent.  It  may  be  recovered  by  distillation  and  the  residue 
poured  into  acidulated  water. 

Glucosids  are  often  removed  from  the  acid  solution  before 
rendering  alkaline  for  the  isolation  of  the  alkaloids,  by  shaking 
with  chloroform,  benzene,  or  petroleum  ether,  and  decanting, 
or  separating  in  a  funnel.  The  detailed  processes  for  assaying 
opium,  cinchona,  nux  vomica,  etc.,  will  be  found  in  the  United 
States  Pharmacopeia. 

ULTIMATE   ANALYSIS. 

Ultimate  or  elementary  analysis  is  accomplished  by  means 
of  a  combustion  tube  and  furnace  connected  by  means  of  tubing, 
first,  with  a  U-shaped  tube  containing  dry  CaCl2,  and,  second, 
with  a  bulbed  tube  (Geissler's)  containing  a  strong  solution  of 
KHO.  A  gram  or  less  of  the  substance  is  mixed  with  about 
ten  times  as  much  CuO,  placed  in  the  combustion  tube,  and 
heated  for  a  sufficient  period.  The  CuO  helps  to  burn  any 
organic  matter. 

H  is  converted  into  H20,  which  is  absorbed  by  the  Cad., 
and  estimated  as  one-ninth  the  increase  in  weight  of  this  tube. 
C  is  changed  to  C02,  which  is  taken  up  by  the  KHO,  increasing 
its  weight  thereby;  three-elevenths  of  this  increase  represents 
the  C  evolved. 

N  is  usually  determined  by  heating  the  substance  with 
soda-lime  (quicklime  and  caustic  soda)  and  passing  the  NH3 
gas  evolved  into  a  beaker  containing  a  given  quantity  of  nor- 
mal HC1  solution.  The  diminution  in  acidity  is  measured  with 
normal  alkali  solution,  and  from  this  factor  the  weight  of  NH:? 
and  of  N  obtained  by  comparison  of  molecular  and  atomic 
weights.  Or  the  NH3  may  be  passed  into  HC1,  which  is  then 
evaporated  over  the  water-bath,  leaving  a  residue  of  XH4C1. 

S  and  P  are  estimated  by  fusing  the  substance  with  KNO.? 
and  Na2C03  in  a  crucible.  C  and  H  are  driven  off  as  C02  and 
H20,  and  S  and  P  are  oxidized  into  H2S04  and  H3P04,  respect- 
ively. The  fused  mass  is  dissolved  in  water;  ILS04  is  pptd.  by 
BaCl2  as  BaS04;  and  H3P04  by  NH4C1,  NH4OH,  and  MgS04  as 
Mg2P207. 

0  is  generally  determined  by  deducting  the  weight  of  all 
the  other  elements  from  the  total  weight  of  the  substance  taken 
to  be  analyzed.  If  the  organic  compound  is  nitrogenous,  or  if 


FINDING  MOLECULAR  WEIGHT.  285 

it  contains  any  halogens,  a  silver  or  copper  spiral  should  be 
placed  in  the  front  part  of  the  combustion  tube  and  be  kept 
at  a  low  red  heat,  in  order  to  prevent  oxids  of  N  or  the  haloid 
elements  from  going  over  into  the  collection  tubes  and  vitiating 
accurate  results.  Organic  compounds  containing  S  should  be 
oxidized  with  PbCr04  before  being  put  into  the  combustion 
tube. 

FINDING   THE   MOLECULAR   WEIGHT. 

The  molecular  weight  of  a  compound  is  twice  its  vapor- 
density^hence  the  determination  of  the  latter  and  of  the  per- 
centage of  each  element  in  the  compound  furnish  data  from 
which  the  empiric  formula  is  reckoned,,  as  heretofore  described. 
'The  Victor  Meyer  vapor-density  apparatus  consists  of  (1)  a 
large  glass  tube  with  a  bulb  at"  the  bottom  containing  water 
or  some  other  fluid  whose  b.p.  is  constant.  The  stopper  of  this 
tube  is  perforated  and  fitted  with  another  smaller  tube  (2)  with 
a  cork  at  its  upper  end,  in  which  is  held  by  a  wire  support  the 
little  glass  vial  holding  the  liquid  substance  to  be  tested,  and 
which  has  been  carefully  weighed.  This  inner  tube  is  provided 
with  a  side  delivery-tube  (3)  to  allow  the  escape  of  heated  air, 
the  open  end  of  this  branch  tube  being  kept  in  a  cup  (4)  under 
water,  until  the  bubbles  of  air  driven  out  by  the  boiling  liquid 
in  the  bulb  cease  to  appear.  At  this  point  the  vial  is  let  fall, 
and  as  the  liquid  boils  in  the  bulb  the  resulting  vapor  from  the 
added  substance  drives  out  through  the  delivery-tube  an  equal 
volume  of  air,  which  is  collected  in  the  graduated  tube  (5),  or 
eudiometer,  previously  filled  with  water  and  placed  over  the 
open  end  of  the  delivery-tube.  The  vapor-density  is  deter- 
mined from  the  vapor-volume  {4ufi_alLawas€e-beiftg  made  for 
the  temperature  of  formation,  namely;  tha-t-of  the  liquidrin 
the  outer  tube)- by  dividing  the  weight  of  the  substance  taken 
(usually  not  more  than  0.1  gin.)  by  the  weight  of  a  volume  of 
H  equal  to  the  volume  of  air  collected  in  the  eudiometer.  A 
general  formula  for  calculating  vapor-density  according  to  this 
method  is  as  follows  r-^1-- _ 

-p.  S  X  760  XI  .003665  t 

~~  V  X  (B— w)  X  0.001293 

in  which  D  stands  for  density,  8  for  weight  of  substance,  t  for 
temperature,  V  for  volume  of  air  displaced,  B  for  barometric 
reading,  and  w  for  water-vapor  tension  at  the  temperature  of 
the  observation.  As  air  is  14.435  times  as  heavy  as  H,  the 
value  of  D  obtained  in  the  above  formula  must  be  multiplied 
by  this  factor. 

Another  method  of  determining  the  molecular  weight  of 


286 


ANALYSIS. 


organic  substances  is  by  dividing  the  constant  of  Jf.p.  depression 
in  solvents  (19  for  water)  by  the  actual  lowering  of  this  point 
in  a  given  solution  of  a  certain  strength,  calculated  to  1  per 
cent,  of  the  solvent.  The  process  depends  upon  the  law  of 
Raoult:  Solutions  containing,  in  equal  volumes  of  a  solvent, 
quantities  of  dissolved  substances  proportional  to  their  molec- 
ular weights  have  the  same  f.p. 


Fig.  44. — Victor  Meyer  Apparatus. 
ANALYSIS    OF   AMALGAM   ALLOYS. 

The  qualitative  tests  are  readily  effected  by  treating  the 
alloy  with  HN03  (1.20),  which  dissolves  out  all  the  metals 
except  Sn  and  Sb  (oxidized)  and  Au  and  Pt.  Sb  and  Sn  are 
removed  from  the  residue  by  hot  strong  HC1,  and  then  the  Au 
and  Pt  may  be  taken  up  with  aqua  regia.  The  acid  solutions 


REFINING  OF  GOLD.  287 

should  be  evaporated  to  dryness  at  a  moderate  heat  and  the 
nitrates  or  chlorids  taken  up  with  water,  filtered,  and  analyzed 
in  the  ordinary  way. 

The  quantitative  analysis  embraces  the  following  steps: — 

1.  Boil  with  HN03  in  a  beaker  to  dissolve  Cu  (may  be 
green  or  blue),  Ag,  Zn,  and  Cd,  but  not  Au,  Pt,  -Sb,  or  Sn 
(whitish  ppt.  if  alone;   colored  light  to  deep  purple  if  Au  pres- 
ent, dirty  black  if  Pt  or  Pt  and  Au).     Evaporate  to  dryness 
over  water-bath,  add  distilled  water,  stir  well,  and  filter. 

2.  Throw  down  Ag  with  HC1,  reduce  to  a  button  of  the 
metal,  and  weigh.     Filter. 

3.  Add  10  per  cent.  NH4OH  to  ppt.  Cu  (blue)  if  present, 
and  filter. 

4.  H2S  gives  a  black  (Cu)  or  yellow  (Cd)  ppt.;  a  brownish- 
yellow  color  means  that  not  all  the  silver  has  been  pptd. 

5.  Boil  filtrate  of  No.  4  down  nearly  to  dryness  (to  expel 
H2S),  dilute,  and  neutralize  with  Na2C03.    A  white  ppt.  =  Zn. 

6.  To  estimate  Sn  ignite  the  residue  thoroughly;  then  cool 
and  weigh.     The  resulting  Sn02  multiplied  by  0.788  gives  the 
actual  weight  of  Sn.    If  Au  is  also  present,  the  Sn  is  calculated 
by  difference  after  finding  the  weight  of  the  gold. 

7.  Au  and  Pt  are  dissolved  by  aqua  regia.     The  Pt  may 
be  pptd.  by  treating  the  aqueous  solution,  after  evaporating  the 
acid,  with  NH4C1  and  alcohol;  the  ppt.  is  heated  and  weighed. 
The  gold  is  then  pptd.  with  FeS04  or  H2C204,  heated  to  redness 
and  weighed. 

8.  Hg  is  easily  determined  by  weighing,  heating  to  redness, 
and  weighing  again;   the  difference  represents  this  metal,  the 
vapors  of  which  discolor  ammonio-silver  nitrate  on  filter-paper. 


REFINING   OF  GOLD. 

Dry  Method. — Heat  a  clean  clay  crucible  to  redness  in  the 
furnace,  place  in  the  gold,  add  a  few  crystals  of  saltpeter,  re- 
place the  furnace-cover,  and  melt  the  gold  quickly.  Clean  and 
oil  an  ingot  mold,  keep  it  warm  while  the  gold  is  melting,  and 
pour  the  metal  into  it  by  means  of  tongs.  Then  remove  the 
ingot,  wash  it,  and  anneal  it  to  a  cherry-red;  plunge  into  dilute 
H2S04,  wash,  dry,  roll,  and  reanneal.  If  the  ingot  cracks, 
transfer  it  again  to  the  crucible  and  heat  as  high  as  possible 
until  molten,  add  some  more  crystals  of  saltpeter,  turning  the 
crucible  so  as  to  mix  well,  continue  roasting  for  some  time,  and 
pour  again  into  the  mold.  All  the  baser  metals  except  Sn  are 
oxidized  by  KN03,  and  Sn  is  readily  chloridized  by  heatin^ 
with  HgCl2.  . 


288 


ANALYSIS. 


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ANALYSIS. 


OTHER  REACTIONS  AND  TESTS. 

ilute  solution  touched  to  tongue 
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a.2CO3  ppts.  white  alkaloid  ; 
soon  turns  green  and  colors 
chloroform  blue  or  violet. 

reak  solution  dilates  pupil  ;  Au- 
C13  gives  a  yellow  ppt. 

ed  color  on  dissolving  in  HCI 
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resh  Cl  water  colors  brucin 
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C103  +  HCI  oxidize  cafFein  or 
thein  ;  products  turn  purple- 
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egative  to  quinin  tests  ;  salt 
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athit  test. 

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acal  anesthetic  and  mydriatic. 
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HNO3  residue  turns  violet 
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Dilates  pupils. 

AuCl3  gives  a  yellow  crysta 
ppt.,  soluble  in  boiling 
acidulated  with  HCI. 

Yellow  ppts.  with  AuCl3,  P 
chromates,  or  picric  acid 
duces  AgNO8,  etc. 

Fine  red  residue  from  evapor 
dilute  H2SO4  solution. 

Characteristic  odor.  AuCi 
PtCl4  gives  light-yellow  pj 

CaClo  colors  red  ;  turns  gm- 
heating.  A  trace  conti 
pupil. 

Myotic  and  sudorific  ;  tritur 
with  calomel,  turns  black  \v 
breathed  on. 

Sharp,  biting  sensation  on  h 
ing  on  tongue  ;  HC2H302 
+  Wo2-recf. 

Solution  (fluorescent)  slu 
with  Cl  or  Br  water  t 
bright  green  on  adding  I 
nw 

Ceroso-ceric  oxid  added  1 
trace  dissolved  in  a  dro 
H2SO4  shows  blue,  violet, 

Br  water  colors  violet. 

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ANALYSIS. 


Wet  Method. — Dissolve  in  aqua  regia  (which  ppts.  AgCl), 
let  settle,  and  pour  off  supernatant  liquid,  and  add  gradually  to 
this  a  clear,  filtered  solution  of  FeS04  (5  parts  for  1  of  gold). 
Au  is  thrown  down  as  a  brown  powder.  Let  settle,  filter,  and 
wash;  digest  deposit  in  dilute  H2S04,  filter  again,  wash  well, 
and  melt  powder  to  a  button  in  furnace. 

QUESTIONS  ON  ANALYTIC   CHEMISTRY. 

1.  Which  is  the  more  delicate  test  reagent  for  Pb,  HC1  or  H2S? 

2.  What  is  the  black  ppt.  formed  when  NH4OH  is  added  to  a  mer- 
curous  solution? 

3.  What  is  the  gray  ppt.  obtained  by  boiling  HgCl2  with  a  stan- 
nous  solution? 

4.  Why  cannot   H2S  be  employed   in   a   solution   containing   free 
HNOa?     How  separate  the  silver  from  the  copper  in  a  dime? 


Fig.  45.— Dental  Furnace. 


5.  What  is  the  object  of  NH4C1  in  the  third  group  reagents? 

6.  How  can  one  obtain  Cu  from  a  solution  in  KCN? 

7.  What  is  the  formula  of  the  ppt.  obtained  by  adding  KC1  to  a 
Pt  solution? 

8.  Why  does  Ag.2CO3  turn  black  on  heating? 

9.  Explain   reddish-brown   change   of  color   on   treating   Prussian 
blue  with  alkalies.     How  do  acids  restore  the  blue  color? 

10.  Why  is  charcoal  used  for  reduction  tests? 

11.  What  weight  of  Ca(HO)2  in  10  c.c.  of  a  decinormal  solution  of 
this  compound? 

12.  Calculate  the  neutralizing  equivalent  of  potassium  acetate. 

13.  What   is  the  brownish  ppt.   obtained  by  heating  cocain  with 
dilute  H2SO4,  neutralizing  with  KHO  and  adding  Fe2Cl8? 

14.  Mention  five  analytic  distinctions  between  As  and  Sb. 

15.  How  much  CuSO4  does  48  gm.  of  pptd.  CuO  represent? 

16.  In  preparing  a  normal  acid  solution,  if  10  c.c.  of  normal  alkali 
neutralize  6.8  c.c.  of  the  dilute  acid,  what  percentage  of  water  must  be 
added  to  the  latter  to  complete  the  preparation? 

17.  How  many  c.c.  approximately  of  concentrated  H,S04  and  HC1 
are  required  to  make  a  normal  solution  of  each? 


SPECIAL  EXAMPLES.  301 

Antipyrin  incompatible  with  phenol,  alum,  HgCl2,  beta- 
naphtol,  syrup  of  FeI2,  and  precipitants  of  alkaloids. 

Chloral  or  chloralamid  decomposed  by  alkalies,  forming 
CHC13  and  a  formate  of  the  alkali. 

Tartar  emetic  incompatible  with  tannin  and  antipyrin. 

Carbolic  acid  coagulates  collodion. 

Mercuric  salts  coagulate  albumin  (soluble  in  excess  of 
albumin)  and  gelatin,  and  ppt.  tannin. 

Borax  forms  a  gelatinous  mass  with  acacia — liquefied  by 
adding  sugar. 

Glucosids  decomposed  into  glucose,  etc.,  by  free  acids  or 
emulsin. 

Pepsin  is  pptd.  by  many  metallic  salts. 

Pepsin  and  pancreatin  are  coagulated  by  strong  alcohol 
into  a  flocculent  rubber-like  mass. 

Acids  decompose  Bi  solutions. 

Nitrous  ether  darkens  with  tannin  or  tannates,  liberates 
I  from  iodids,  and  is  broken  up  by  acids  and  alkalies,  liberating 
gases  very  freely.  It  gives  a  green  color  with  antipyrin;  a 
yellow  or  red  with  acetanilid. 

Compound  ethers  are  incompatible  with  alkalies,  forming 
alcohol  and  salts. 

lodin  or  Ag20  forms  a  very  explosive  compound  with  am- 
monium hydrate  or  salts;  NHI2  explodes  when  dry. 

Tincture  of  I  is  decolorized  by  tannin  or  NH4HO  (forms 
NHJ). 

Gallic  acid  gives  a  green  or  brown  coloration  with  hydrates 
or  carbonates,  blue  with  lime-water,  bluish  black  with  Fe2Cl6. 

Strong  acids  decompose  ammonio-citrate  of  bismuth. 

Bismuth  subnitrate  forms  a  red  compound  with  I  and  with 
salicylic  acid,  and  liberates  C02  in  a  fluid  mixture  with  bicar- 
bonates. 

Ferric  chlorid  produces  a  violet  color  with  carbolic  and 
salicylic  acids  and  their  salts,  creasote  (quickly  fades  brown), 
.phenol  radicals  (salol,  anilin,  resorcin,  cresols,  guaiacol),  and 
oils  of  cloves,  bay,  and  pimenta;  red  color  with  acetates,  sulpho- 
cyanids,  antipyrin,  and  acacia;  flesh  color  with  benzoic  acid 
and  benzoates;  green  with  guaiac,  aloin,  thallin;  blue-black 
with  gallic  acid;  black  with  tannic  acid,  tannates,  and  gentian. 

All  reducing  agents  (FeSOJ  ppt.  gold  from  its  solutions 
as  a  brick-red  powder. 

Alkaloidal  salts  form  insoluble  santalates  with  compound 
tincture  of  lavender. 


302  INCOMPATIBILITY. 


LIQUEFACTION  ON  TRITURATION. 

(Substances  generally  insoluble  in  water.) 
Antipyrin  with  chloral,  sodium  salicylate,  or  euphorin. 
Sodium  salicylate  with  acetanilid,  exalgin,  etc. 
Chloral  with  camphor,  menthol,  phenol,  or  thymol. 
Camphor  with  betanaphtol,  butyl  chloral,  menthol,  phenol, 
thymol,  and  resorcin. 

Butyl  chloral  writh  camphor,  menthol,  phenol,  or  thymol. 
Thymol  with  chloral,  menthol,  or  phenol. 
Exalgin  with  salicylic  acid. 

CHEMIC  DECOMPOSITION  ON  TRITURATION. 

Commercial  KC103  may  explode  singly  under  sharp  con- 
tusion. 

Hypophosphites  triturated  alone  may  d  Compose,  forming 
H3P  with  explosion. 

lodol  rubbed  with  yellow  HgO  explodes. 

Potassium  chlorate  may  explode  when  rubbed  with  S,  tan- 
nin, or  picric  acid. 

Potassium  nitrate  is  explosive  when  triturated  with  S  and 
dry  K2C03;  K2Mn208  with  picric  acid  and  tannin;  K2Cr207 
with  tannic  and  picric  acids. 

Oxid  of  silver  should  not  be  rubbed  with  dry  organic  sub- 
stances. 

Mercurous  salts  are  generally  reduced  to  metallic  Hg  and 
HgCl2  when  rubbed  with  other  salts.  This  poisonous  change 
may  be  prevented  by  moistening  with  a  little  alcohol,  water, 
or  oil  before  rubbing: — 

2HgCl  +  2KBr  =  HgBr2,2KCl  (very  poisonous)  +  Hg 

INCOMPATIBILITIES  OF  WATER. 

Bismuth  nitrate  forms  insoluble  basic  nitrate. 

Water  ppts.  SbCl3  as  SbOCl. 

Subacetate  of  lead  carbonates  and  forms  a  cloudy  mixture 
with  water  which  has  stood  in  contact  with  the  air. 

Mercuric  salts  and  HgN03  are  decomposed  (except  HgCl2), 
requiring  KI  or  free  acids  to  effect  solution. 

Tincture  of  digitalis,  when  mixed  with  aqueous  or  syrupy 
solutions,  may  decompose,  forming  new  and  poisonous  prin- 
ciples. 

Sodium  peroxid  breaks  up  with  wrater  into  NallO  and  0. 


PRESCRIPTIONS.  303 


INTENTIONAL  INCOMPATIBILITY. 

This  is  illustrated  by  black  and  yellow  wash  and  by  silver 
nitrate  and  acetate  of  lead  with  opium. 


PRESCRIPTIONS. 

Prescribe  salts  and  acids  with  the  same  radical  whenever 
practicable — as  tinct.  ferri  chloridi,  liq.  arsen.  chloridi,  acidi 
hydrochlorici,  and  hydrarg.  chloridi  corros. 

The  following-named  substances  are  best  given  alone  in 
simple  solution:  Chlorin-water,  citrate  of  iron  and  quinin,  di- 
lute hydrocyanic  or  nitrohydrochloric  acid,  iodin,  and  iodids; 
liquors  calcis,  ferri  nitratis,  potass,  and  potassii  arsenitis;  mor- 
phin  acetate  or  hydrochlorate;  potassium  acetate,  bromid,  or 
permanganate;  qrinin  sulphate;  syrup  of  iodid  of  iron;  tannic 
and  gallic  acids;  tartar  emetic;  tinct.  ferri  chloridi  and  guaiaci; 
zinc  acetate. 

The  following  combinations  have  been  known  to  explode: 
Potassium  chlorate  and  hypophosphites  in  water;  potassium 
chlorate,  tannin,  and  glycerin;  K2Mn208,  tincture  of  iron,  and 
glycerin;  HX03,  HC1,  and  tinct.  nucis  vomicaB;  borax,  NaHC03, 
glycerin,  and  H20  (evolution  of  C02);  K2Mn208,  alcohol,  and 
water;  oil  of  amber  and  HN03;  turpentine  and  H2S04;  I  and 
spirit  of  camphor;  O03  and  glycerin.  Mixtures  of  NH4C1  and 
KC103  have  exploded  violently  after  standing  awhile. 

Kaolin,  talcum,  fuller's  earth,  petroleum,  and  paraffin  are 
the  best  excipients  for  pills  and  triturates  of  silver  salts  (coated 
with  Tolu),  potassium  permanganate,  and  dichromate. 

ACTION  OF  AIR,  LIGHT,  AND  ATMOSPHERIC  HEAT. 

HYGROSCOPIC  AND  DELIQUESCENT. 

.,    ,  .  EFFLORESCENT  COMPOUNDS. 

(Not  to  be  prescribed  in  cachets.) 

Acids:    Carbolic,  chromic,  citric.  Citric  (sometimes). 

Aluminum:    CMorid,  bromid,  iodid,  ace-       Phosphate,  valerate. 
tate. 

Ammonium:     CMorid,  bromid,  iodid,  ni- 
trate. 

Amylen :    Hydrate. 

Antimony:    Chlorid.  Tartrate   (SbOK). 

Barium :  Acetate. 

Calcium:     Clilorid,    bromid.    iodid,    Otfid,       Acetate, 
hypoclilorite. 

Chloral:    Hydrate  and  butyl. 

Cinchonidin:  Sulphate. 


304 


INCOMPATIBILITY. 


HYGROSCOPIC  AND  DELIQUESCENT. 
(Not  to  be  prescribed  in  cachets.) 

Cobalt:    Acetate,  chlorid,  nitrate. 

Copper:     Chlorid,  nitrate. 

Ferric:    Chlorid  and  scale  compounds. 

Ferrous:  Chlorid,  bromid,  iodid,  phos- 
phate. 

Gold:    Chlorid. 

Hyoscyamin:     Hydrochlorate,  sulphate. 

Lead: 

Lithium:  Chlorid,  bromid,  iodid,  salic- 
ylate. 

Magnesium:  Chlorid,  bromid,  iodid,  cit- 
rate. 

Manganese:  Chlorid,  bromid,  iodid,  ni- 
trate. 

Physostigmin:    Sulphate. 

Pilocarpin :    Hydrochlorate. 

Platinum:    Chlorid. 

Potassium:    Salts  generally. 

Quinin:  Bisulphate,  sulphate,  hydrochlo- 
rate,  hydrobromate. 

Sodium :  Hupophosphite,  hydrate,  haloids, 
nitrate. 

Spartein :     Sulphate. 

Strontium:    Chlorid,  bromid,  iodid. 

Strychnin  : 

Zinc:    Chlorid,  bromid,  iodid,  nitrate. 


EFFLORESCENT  COMPOUNDS. 

Sulphate. 

Acetate,  sulphate. 
Ferric  alum. 
Sulphate. 


Acetate. 

Sulphate. 
Sulphate. 

Tart  rate  (KNa),  ferrocyanid. 
Carbonate. 


Acetate,  nitrate. 
Sulphate. 
Acetate,  sulphate. 

Granular  effervescing  and  exsiccated  salts,  pepsin,  codein,  acid  phos- 
phates, glycerophosphates,  piperazin,  lysidin,  and  dry  vegetable  ex- 
tracts. 

Color-changes.  —  Carbolic  acid  turns  red  (just  as  good); 
resorein,  pinkish,  yellow,,  or  deep  brown  (especially  if  exposed 
even  to  traces  of  alkalies);  apomorphin  hydrochlorate,  green- 
ish (prevented  by  HC1);  nitric  acid,  bromoform,  aconitin,  san- 
tonin, and  sodium  santoninate,  yellowish;  cinchonin  and  cin- 
chonidin  salts  and  quinin  salts,  brownish;  permanganate  solu- 
tions, decolorized.  All  Ag  salts,  ferrous  salts  (from  green  to 
bluish  or  reddish  brown),  ferric  scale  compounds,  iodoform, 
HgO,  Hg(CN)2  and  HgI2,  Hg2I2,  pyrogallol,  syrup  of  garlic, 
oleates,  and  chrysarobin  darken  from  reduction  or  oxidation. 
HCN  becomes  brown,  then  black  (paracyanogen)  (prevented  by 
a  little  HC1).  Salicylates  darken  in  the  presence  of  the  slightest 
trace  of  alkali.  Acetanilid  with  spirit  of  nitrous  ether  develops 
slowly  a  yellow  or  red  color.  Osmic  acid  blackens  in  contact 
with  organic  matter.  Sulphurated  potash  oxidizes  from  a  liver 
color  to  green,  then  yellow  (K2S03  +  K2S704),  and  finally  dirty 
white  (K2S04  -f-  K2S203).  Syrup  of  HI  is  reduced  by  light, 
liberating  free  I,  with  brown  or  yellow  color  (specimen  unfit 
to  use  if  it  turns  starch-paper  blue). 


PRACTICAL  EXERCISES.  305 

Reduction. — Ammonium  salts;  synthetic  iodin  compounds 
(iodoform,  aristol,  europhen);  chinolin,  lead  acetate,  KCN; 
alkaline  bi-salts;  zinc  acetate,  iodid,  phosphid,  and  valerianate. 
Ferric  acetate,  chlorid,  and  nitrate  become  basic  and  insoluble. 

Oxidation. — Hypophosphites,  nitrates,  sulphids,  sulphites, 
ferrous  salts,  pyrogallol,  tannin  solutions,  P  (spontaneous  igni- 
tion), aldehyds  (most  alcoholics  contain  traces),  all  tend  to 
darken,  especially  in  the  presence  of  alkalies.  Amyl  nitrite 
and  aqueous  solutions  of  chloral  become  acid.  Terebene  and 
terpenes  become  resinous  and  acid.  FeS04  becomes  coated 
with  a  brownish-yellow  crust  of  basic  ferric  sulphate.  Spirit 
of  nitrous  ether  liberates  free  nitrous  acid  quickly  in  the  light. 
Oleic  acid  becomes  rancid.  Mucilage  of  acacia  turns  sour  and 
acid  on  standing,  unless  some  preservative  is  used. 

Carbonation. — Lead  acetate,  lime,  bleaching  powder,  KCN,. 
and  bicarbonates  generally. 

Evaporation. — Camphor,  chloral,  menthol,  thymol,  volatile 
oils,  alcohols,  and  ethers. 

Spontaneous  combustion  usually  occurs  in  compounds  con- 
taining C,  0,  and  Cl:  creasote  and  Ag20;  K2Mn208  and  glyc- 
erin or  oxalic  acid. 


PRACTICAL   EXERCISES   ON  INCOMPATIBILITIES. 

(Criticise  and  correct,  if  possible,  and  illustrate  in  test-tube  or  cas- 
serole.) 

1.  IJ  Acidi  acet.  dil.,  3ij ;  spt.  ammon.  arom.,  3vj. 

2.  IJ  Argenti  nitratis,  gr.  x;  aquae  rosae,  j$j. 

3.  IJ  Sodii  salic.,  gr.  xv;  ammonii  carb.,  gr.  v;  spt.  aetheris  nitrosi, 
w?xv;  spt.  chloroformi,  w/x;  aquam,  ad  3j- 

4.  IJ  Tinct.  ferri  chloridi,  3ij;  quin.  sulph.,  3j;  tinct.  cinchonas,  3rj- 

5.  IJ  Hydrogen,  diox.,  3iv;  potassii  permang.,  3j;  glycerin,  ad  gj. 

6.  IJ  Potassii    chloratis,    3j;    tinct.   ferri    chloridi,    3iv;    glycerin,, 
ad  3ij. 

7.  IJ  Potassii  iodidi,  3ij;  strych.  sulph.,  gr.  ss;  aquae,  3ij. 

8.  IJ  Liq.  potassii  arsenitis,  3ij;   hydrarg.  chloridi  corros.,  gr.  j; 
aquae,  5iv. 

9.  IJ  Hydrarg.  bichloridi,  gr.  xx;  sodii  boratis,  3ij;  aquae,  giv. 

10.  IJ  Quin.  sulph.,  3j;  acidi  sulph.  arom.,  3j ;  potassii  acetat.,  Siv;. 
aquam,  ad  3iv. 

11.  IJ  Syrupi  scillae,  3iv;  spt.  ammon.  arom.,  3iv;  aquas,  5j. 

12.  IJ  Zinci  sulphatis,  gr.  ij;  liquoris  calcis,  3j. 

13.  IJ  Liq.  potassii  arsenitis,  3j;  hydrarg.  bichloridi,  gr.  ss;  strych. 
sulph.,  gr.  Y.,;  aquam,  ad  %ij. 

14.  IJ  Plumbi  acetatis,  3j;  zinci  sulphatis,  gr.  xx;  alum,  sulph.,  3j; 
aquae,  3j- 

15.  IJ  Acidi  chromici,  gr.  xxx;  glycerini,  3iv. 

16.  IJ   Quin.  sulph.,  3iss;  tinct.  ferri  chloridi,  3iij;  ext.  glycyrrhizse 
fl.,  3j ;  aquam,  ad  Siv. 

20 


306  INCOMPATIBILITY. 

17.  I£  Spt.   camphorse,   Sss;    spt.   chloroformi,   5ss;    aquae   menthae 
Pip-,  5j. 

18.  IJ  Infusi  gentianae  comp.,  §ij ;   infusi  digitalis,  5j ;    infusi  cin- 
chonas, 3j- 

19.  Ifc  Tinct.  guaiaci,   3iv;    sodii   salicylatis,   3ij;    aquam  menthae 
"  iridis,  ad  %ij. 

20.  I£  Spt.  menthae  pip.,  3ij;  tinct.  capsici,  3iv;  aquam,  ad  3j. 

21.  R  Acidi  nitrohydrochlorici,  3iv;  tinct.  cardam.  comp.,  §iss. 

22.  IJ  Sodii  salic.,  3ij ;  acidi  hydrochlor.,  3j ;  aquam  menthae  viridis, 
ad  Sij. 

23.  I£  Ammon.  carb.,  3j;   ammon.  chloridi,  gr.  xxx;   syrupi  scillae, 
5j;  syrupi  ipecac.,  §j;  syrupi  prun.  Virg.,  Sij- 

24.  IJ  Tinct.  ferri  chloridi,  3ij;  acidi  carbolici,  3ss;  glycerin,  ad  §j. 

25.  I£  Collodii  flex.,  tinct.  iodi,  aquae  ammonise,  of  each,  3iv. 

26.  How  combine  tincture  or  fluid  extract  of  cannabis  Indica  with 
an  aqueous  solution? 

27.  Explain  the  effervescence  of  spirit  of  nitrous  ether  with  buchu 
or  uva  ursi. 

28.  Explain  effervescence  in  making  Dobell's  solution. 

29.  What  objection  to  magnesia  alba  as  a  distributing  agent  for 
the  preparation  of  aromatic  waters? 

30.  Under  what  circumstances  will  spirit  of  nitrous  ether  give  a 
brown  color  with  iodin? 

31.  What  causes  the  effervescence  when  glycerin,  borax,  and  fluid 
extract  of  licorice  are  mixed  together? 

32.  If  a  ppt.  ensues  on  dissolving  calcium  hypophosphite  in  distilled 
water,  what  adulteration  is  present? 


SANITARY  CHEMISTRY. 


THE  AIR. 

AIR  is  contaminated  by  respiration,  combustion,  fermenta- 
tion, putrefaction,  and  various  trade  and  manufacturing  proc- 
esses. The  C02  in  the  air  should  not  exceed  6  parts  in  10,000 
when  of  respiratory  origin;  at  this  point  vitiation  is  noticeable 
to  the  sense  of  smell.  One  pound  of  coal  requires  240  cubic 
feet  of  air  for  complete  combustion,  and  gives  off  3  pounds 
of  C02.  One  cubic  foot  of  coal-gas  combines  with  5  to  8  cubic 
feet  of  air.  A  common  gas-burner  consumes  about  4  cubic 
feet  of  air  hourly  and  furnishes  about  2  cubic  feet  of  C02;  1200 
cubic  feet  of  fresh  air  is  sufficient  for  every  cubic  foot  of  gas 
consumed.  The  vitiation  of  air  from  decomposing  organic 
matter  increases  pari  passu  with  the  amount  of  C02;  hence  the 
latter  is  a  measure  of  the  former. 

Experiment. — Test  the  CO2  of  the  atmosphere  quantitatively  with 
decinormal  oxalic  acid  solution  and  lime-water:  standardize  100  c.c.  of 
latter  with  former,  then  take  another  100  c.c.  of  the  lime-water,  shake 
in  a  bottle  of  known  capacity,  and  titrate  again  with  the  decinormal 
solution.  The  difference  in  c.c.  between  the  two  titration  readings  = 
Ca(HO)2  pptd.  as  CaCO3.  This  difference  X  0.0037  =  weight  of  the 
hydrate  changed  to  carbonate;  and  this  product  X  *Y74  —  weight  of  C02 
causing  the  change.  By  comparing  the  weight  found  of  C02  with  the 
weight  of  the  same  volume  of  air  (1.29  gm.  per  liter)  the  actual  propor- 
tion of  the  gas  is  determined.  Simply  stated,  a  liter  of  in-door  air  should 
not  decolorize  (from  phenol-phthalein)  more  than  1.3  c.c.  of  saturated 
lime-water  after  standing  several  hours. 

Air  containing  an  excess  of  C02  is  detrimental  to  the 
health  more  from  the  coincident  diminution  of  0  and  the  con- 
comitance of  organic  matter  than  on  account  of  the  C02  per  se; 
as  much  as  10  per  cent,  has  been  borne  when  simply  added  to 
the  respired  air.  A  slight  excess  of  C02  in  sleeping-rooms  leads 
to  morning  fatigue  and  drowsiness.  Chronic  C02  poisoning 
leads  to  anemia  and  debility  and  predisposes  to  infectious  dis- 
eases, particularly  phthisis.  CO,  is  greatly  increased  in  ground- 
air;  0  is  diminished. 

The  proportion  of  water  in  in-door  air  varies  greatly  with 
local  conditions,  both  within  and  without  the  house.  Too  little 
moisture  causes  a  disagreeable  dryness  of  the  throat  and  fauces; 
too  much  predisposes  to  rheumatism  and  other  diseases.  One 

(307) 


308  SANITARY  CHEMISTRY. 

pound  of  fresh  lime  left  in  a  room  for  twenty-four  hours  ought 
not  to  increase  more  than  1  per  cent,  in  weight  from  absorption 
of  water-vapor. 

The  most  important  impurities  of  the  atmosphere  include 
NH3  (from  stables,  vaults,  and  animal  exhalations);  H2S,  NH4- 
HS,  and  CS2  (from  decomposition  of  substances  containing  S); 
S02  and  mineral  acids,  especially  nitrous  and  nitric  (from 
combustion  and  electricity);  amins,  ptomains,  and  leucomains. 
H2S03  in  the  atmosphere  may  make  the  rain  acid,  with  de- 
structive effect  on  mortar  and  soft  building-stone.  Sore  throat 
and  bronchitis  are  sometimes  caused  by  leaking  illuminating 
gas,  soot,  or  H2S03. 

The  organic  matter  from  the  skin  and  lungs  consists  of 
epithelia,  fatty  debris,  and  volatile  fatty  acids.  These  putrefy 
very  quickly,  giving  rise  to  the  bad  smell  of  close  rooms,  and 
are  absorbed  by  water  and  hygroscopic  substances.  This  or- 
ganic matter,  reckoned  as  albuminoid  ammonia  (see  "Water"), 
should  not  exceed  0.08  mg.  per  cubic  meter. 

Experiment. — Blow  through  a  glass  tube  into  Nessler's  solution 
and  show  that  NH3  is  present  in  exhaled  air.  Nessler's  reagent  is  made 
by  dissolving  35  gm.  of  KI  in  100  c.c.  of  H2O,  and  17  gm.  of  HgCl2  in  300 
c.c.  of  H2O;  add  first  solution  to  second  until  ppt.  at  first  formed  nearly 
redissolves,  and  make  up  to  a  liter  with  20  per  cent.  NaHO.  The  solution 
is  improved  by  keeping;  any  deposit  may  be  left  in  and  the  clear  fluid 
above  decanted  as  needed.  It  gives  a  yellow  to  brown  color  or  ppt.  with 
free  ammonia. 

A  known  volume  of  air  may  be  sucked  by  an  aspirator  through  a 
specially  arranged  apparatus  containing  ammonia-free  distilled  water, 
and  the  liquid  then  analyzed  for  free  and  albuminoid  NH3,  like  a  water. 

There  is  always  in  poorly  ventilated  houses  a  considerable 
quantity  of  animal  and  vegetable  debris  floating  in  the  air,  along 
with  many  varieties  of  germs,  some  of  which  are  pathogenic. 

Experiment. — Prove  organic  matter  in  exhalations  by  blowing  into 
a  very  weak  solution  of  K2Mn2O8  acidulated  with  H2SO4.  The  solution 
is  decolorized. 

Aitken  has  found  that  condensation  of  aqueous  vapor  re- 
quires the  presence  of  dust  in  the  atmosphere.  By  means  of 
an  ingenious  mirror  apparatus  he  has  counted  the  number  of 
particles  of  dust  in  a  given  space  at  various  places  and  times. 
He  estimates  that  ordinary  still  out-door  air  contains  from 
1,000,000  to  5,000,000  particles  per  cubic  inch;  that  of  living- 
rooms,  20,000,000  to  100,000,000.  The  amount  of  matter  sus- 
pended in  the  air  is  less  after  a  rain  or  snow-storm  and  in  higher 
altitudes.  The  more  dust,  the  more  microbes  in  the  air.  By 
the  time  the  air  reaches  the  pulmonary  vesicles  it  is  usually 
sterile. 


WATER.  309 

Most  infectious  diseases  are  propagated  by  the  passage  of 
germs  through  the  air;  hence  the  necessity  of  isolating  and 
confining  patients  with  such  disorders.  By  proper  ventilation 
deleterious  substances  in  the  air  of  rooms  are  greatly  diluted, 
and  the  health  of  the  occupants  conserved. 

An  adult  individual  at  rest  should  be  supplied  with  3000 
cubic  feet  of  fresh  air  per  hour: — 

i^  =  0.6  CO2  per  1000,— the  limit  of  health. 


D  ( d  r         \  —  E  (amount  of  CO2  exhaled)  _     0.6 

r  (respiratory  impurity  per  cubic  foot)       0.0002 
cubic  feet  per  hour  ;  BO  that  the  respiratory  impurity  may  not  exceed  0.2 
per  1000. 

The  vegetable  and  mineral  matters  inhaled  by  persons 
following  certain  occupations — as  millers,  bakers,  textile  work- 
ers, cutlers,  lapidists,  miners,  quarrymen,  stone-cutters,  and 
potters — tend  to  irritate  and  produce  disease  of  the  lungs,  espe- 
cially emphysema,  fibroid  phthisis,  and  chronic  interstitial  pneu- 
monia and  pneumonokoniosis.  Poisoning  from  Pb,  Hg,  As,  or 
brass  may  take  place  through  the  air. 

The  so-called  noxious  or  offensive  trades  are  those  of  boil- 
ers of  blood,  bones,  tripe,  or  soap;  tallow-melters,  fellmongers, 
tanners,  gut-scrapers,  and  glue-makers. 

Acute  mephitic  poisoning  from  open  foul  drains  and  cess- 
pools is  characterized  by  sudden  severe  vomiting  and  purging, 
headache,  acute  prostration,  and  sometimes  partial  asphyxia. 
The  long-continued  inhalation  of  sewer-gas  and  drain-air  pro- 
duces gradual  loss  of  health,  with  anemia,  lassitude,  headache, 
sore  throat,  diarrhea,  vomiting,  and  often  fever. 


WATER. 

Natural  waters  are  more  or  less  pure  according  to  their 
source  and  course.  For  convenience  they  may  be  classified  as 
potable  (drinkable)  and  mineral,  the  latter  being  unfit  for  ordi- 
nary use,  but  presumably  good  for  sick  people. 

Potable  water  includes  that  from  rain,  snow,  ice,  lakes, 
ponds,  rivers,  springs,  wells,  and  cisterns.  The  purest  natural 
water  is  that  from  snow  falling  on  mountains.  The  latter  part 
of  a  rain-fall  or  snow-fall  is  purer  than  the  first  part,  as  many 
impurities  are  by  this  time  washed  out  of  the  air.  Among  the 
most  common  of  these  contaminations  are  NaCl,  H,S04,  HN"03, 
H2S,  S02,  NH4  salts,  soot,  mineral  dust,  and  organic  matter. 


310  SANITARY  CHEMISTRY. 

Rain-water  from  roofs  and  that  collected  in  large  cisterns  is 
notoriously  unfit  to  drink,  the  contained  organic  matter  under- 
going putrefaction  in  a  few  days;  the  water  from  cisterns  may 
also  contain  Pb. 

The  usual  source  of  hydrant-water  is  from  ponds,  lakes, 
and  rivers:  that  is,  surface-water.  It  is  very  important  that 
no  sewage  enters  the  stream  above  the  site  whence  the  supply 
is  drawn. 

The  relative  purity  of  ice-water  depends  on  its  source.  It 
is  always  purer  than  the  water  from  which  it  was  formed,  but 
may  still  contain  dangerous  germs  (typhoid,  cholera)  or  their 
spores  capable  of  originating  deadly  diseases.  The  flat  taste 
of  ice-water  is  due  to  the  expulsion  of  dissolved  gases  in  the 
process  of  freezing. 

Spring-water  and  well-water  are,  in  reality,  nothing  else 
than  filtered  rain-water  containing  an  excess  of  C02  frequently, 
and  considerable  mineral  matter  which  the  C02  aids  to  dissolve. 
The  sanitary  condition  of  su.ch  waters  depends  on  the  depth  of 
the  excavation,  the  character  of  the  soil  and  underlying  strata, 
and  the  presence  or  absence  of  decaying  organic  matter  in  the 
area  of  drainage.  Shallow  wells  are  little  more  than  cess- 
pools when  placed  in  the  neighborhood  of  a  barn  or  privy-vault. 
They  drain,  it  is  said,  a  cone  of  earth,  the  base  of  which  has 
a  radius  equal  to  four  times  the  depth  of  the  well.  The  grossly 
polluted  waters  of  many  shallow  wells  are,  as  a  rule,  clear, 
sparkling,  and  palatable;  but  they  quickly  become  turbid  and 
putrid  when  kept  in  a  bottle  in  a  warm  place. 

Deep  wells  are  one  hundred  feet  or  more  in  depth,  or  orig- 
inate beneath  a  stratum  of  rock  or  impervious  clay.  These 
wells  are  safer  than  the  shallow  ones,  especially  if  cased  with 
metal,  since  the  deleterious  organic  matter  at  or  near  the  sur- 
face is  pretty  well  destroyed  by  the  time  it  filters  down  to  the 
source  of  the  well.  Artesian  fountains  are  best  of  all  wells, 
because  the  impervious  stratum  of  clay  that  covers  the  water- 
bed  prevents  access  of  decaying  matter  from  the  surface. 

Mineral  waters,  so  called,  are  characterized  by  containing 
an  unusual  ingredient  or  an  excessive  amount  of  some  ordinary 
constituent.  According  to  the  chemic  nature  of  such  ingre- 
dients, these  waters  are  designated  as  saline  (neutral  salts), 
bitter  (MgS04),  acid  (HC1  and  H2S04),  alkaline  (carbonates  and 
bicarbonates),  chalybeate  (ferrous  sulphate,  chlorid,  or  carbon- 
ate, held  in  solution  by  C02),  silicated  (siliceous  acid),  carbon- 
ated or  effervescent  (excess  of  C02  with  bicarbonates),  alum, 
borax,  and  sulphureted  (H2S  or  alkaline  sulphids)  or  hepatic. 
Waters  that  have  a  laxative  effect  are  termed  aperient.  Many 


WATER.  311 

mineral  waters  belong  to  more  than  one  class.  When  the  tem- 
perature of  a  spring  is  above  20°  C.  it  is  called  a  thermal  spring. 

Mineral  waters  are  highly  vaunted  by  persons  who  are  in- 
terested financially.  As  a  matter  of  fact,  these  waters  have 
little,  if  any,  more  value  than  water  per  se.  The  strongest 
lithia-waters  contain  only  a  fraction  of  a  dose  in  each  gallon. 
In  the  case  of  the  more  common  salts,  their  action  is  often  neu- 
tralized and  one  danger  substituted  for  another  by  the  use  of 
these  waters,  owing  to  the  physiologic  incompatibility  of  the 
various  ingredients.  Their  ingestion  ad  libitum  is  particularly 
to  be  deprecated  in  organic  heart  disease. 

Whatever  good  effects  may  accrue  from  the  administration 
of  mineral  waters  must  be  ascribed  to  the  influence  of  sugges- 
tion, rest,  and  recreation,  change  of  scene,  and  the  action  of 
water  as  water.  It  is  far  more  rational  for  physicians  to  pre- 
scribe distilled  water  with  the  exact  amount  of  each  ingredient 
desired.  The  benefits  derived  in  kidney  and  systemic  diseases 
from  baths  at  hot  springs  depend,  not  on  any  particular  com- 
ponents of  the  water,  but  simply  on  the  diaphoretic  action  of 
moist  heat. 

Sea-water  contains  an  average  of  3  Y2  per  cent,  of  min- 
erals, chiefly  NaCl  (2  2/3  per  cent.),  MgCl2,  MgS04,  and  CaS04. 
It  has  a  local  tonic  effect,  which  reacts  on  the  internal  organs; 
and  the  same  is  true  of  carbonated  baths. 

Water  for  drinking  purposes  should  conform  to  the  follow- 
ing conditions: — 

1.  It  should  be  colorless,  clear,  and  limpid.    Turbidity  may 
be  due  to  either  organic  or  inorganic  impurities.    A  green  col- 
oration (in  small  quantities)  indicates  a  high  degree  of  vege- 
table contamination,  and  is  comparatively  harmless.    Algae  and 
other  micro-organisms  may  color  red  or  greenish  blue.    A  yel- 
low or  brown  color  may  depend  on  animal  matter  or  sewage, 
or  less  often  on  vegetable  debris  or  iron.    Dark-brown,  globular 
masses  usually  originate  in  sewage. 

2.  It  should  be  odorless.    Odors  may  be  brought  out  more 
distinctly  by  heating  the  water  in  a  flask  to  a  little  more  than 
blood-heat.    Foul  odors  usually  accompany  sewer-gas,  algae,  and 
putrefying  organic  matter.     An  odor  like  H2S  may  be  caused 
by  the  penetration  of  tree-roots,  and  is  sometimes  produced  by 
reduction  of  sulphates  through  the  agency  of  putrefactive  bac- 
teria (bacillus  sulphydrogenus). 

3.  It  should  be  of  agreeable  taste:   neither  flat,  salty,  nor 
sweetish.     A  decided  taste  is  commonly  due  to  a  high  charge 
of  mineral  matter,  especially  iron  and  alkaline  carbonates. 

4.  The  most  wholesome  and  desirable  temperature  is  be- 


312  SANITARY  CHEMISTRY. 

tween  45°  and  60°  F.     Warm  storage  water  is  apt  to  set  up 
summer  diarrhea  in  infants. 

5.  The  quantity  by  volume  of  dissolved  gases  should  be 
from  25  to  50  c.c.  per  liter  of  water.    These  gases  are  made  up 
chiefly  of  0  (1  per  cent,  volume),  N"  (2  per  cent,  volume),  and 
C02  (1  per  cent,  or  more  volume).     The  quantity  of  dissolved 
0  is  much  diminished  by  excess  of  animal  and  vegetable  matter, 
and  this  diminution  (usually  in  still  waters)  is  often  accom- 
panied by  a  bad  smell  and  taste.    Boiling  water  drives  off  the 
contained  gases,  giving  rise  to  an  insipid  taste.     The  natural 
taste  can  be  restored  by  aerating;  for  instance,  by  pouring  from 
one  vessel  to  another. 

6.  In  hardness — that  is,  dissolved  inorganic  solids — good 
drinking-water  should  not  exceed  40  grains  to  the  gallon,  or 
2  to  4  parts  per  thousand.    Dyspepsia  and  diarrhea  are  caused 
by  too  much  sulphates  (above  7°  or  8°)  or  by  sewage  (some- 
times choleraic).    It  has  long  been  held  that  hard  waters  are  a 
causative  factor  in  goiter. 

7.  Water  fit  for  internal  use  obviously  should  contain  no 
pathogenic  germs,  as  of  typhoid,  dysentery,  or  cholera.     This 
is  the  most  dangerous  contamination  to  which  drinking-water 
is  subject.     Well-water  is  more  likely  to  cause  enteric  fever 
than  is  river-water,  where  saprophytic  organisms  destroy  typhoid 
germs.     Various  entozoal   diseases  may  also   originate   in  the 
drinking-water. 

PURIFICATION. 

Various  methods  have  been  devised  for  purifying  drinking- 
water  for  public  and  private  consumption.  The  water-supply 
for  cities  is  best  clarified  by  allowing  it  to  settle  for  a  week  or 
so  in  storage  reservoirs,  when  it  is  drawn  off  on  to  filter-beds 
several  feet  in  thickness,  and  composed  mainly  of  coarse  sand 
and  gravel  with  a  layer  an  inch  deep  of  fine  sand  at  the  top. 
This  layer  of  fine  sand  is  the  real  filtering  agent.  It  purifies 
water  chiefly  by  condensation  of  0  in  its  upper  surface  and  the 
entanglement  of  bacteria  in  the  superficial  gelatinous  deposit. 
It  should  be  removed  and  washed  frequently  and  thoroughly. 

Another  method  in  use  on  a  large  scale  is  scouring,  or 
agitation  and  precipitation  of  solids,  both  mineral  and  organic, 
by  the  addition  of  1  or  2  grains  of  alum  to  the  gallon  of  water, 
thus  forming  a  flocculent  magma  which  carries  down  the  silt 
and  other  suspended  impurities  as  with  a  net.  Lime-water  may 
be  used  to  ppt.  excess  of  carbonates.  Magnetic-carbid-of-iron 
beds  are  also  employed  for  purification  on  a  large  scale;  these 


ANALYSIS  OF  WATER.  313 

beds  must  be  aerated  occasionally  to  keep  their  oxidizing  prop- 
erties. Still  another  method  is  to  pass  the  water  through  a 
revolving  cylinder  containing  scrap-iron,  and  then  through  a 
trough,  where  the  ppt.  of  ferric  oxid  carries  down  organic 
matter  with  it. 

In  London  a  living  filter  is  employed  for  the  water  of  the 
Thames.  A  layer  of  mud  containing  billions  of  innocuous 
saprophytes  to  the  cubic  foot  is  spread  over  the  sand  layer  of 
the  filter-bed,  forming  a  jelly-like  crust.  These  germs  seize  on 
all  organic  matter  in  the  water,  oxidizing  and  destroying  it 
completely,  thus  affording  the  most  efficient  sanitary  filter 
possible. 

0  is  commonly  spoken  of  as  Nature's  great  antiseptic,  yet 
in  its  ordinary  molecular  form  it  exerts  this  effect  for  the  most 
part  through  the  agency  of  microbes.  The  great  majority  of 
these  are  not  only  harmless,  but  of  immense  importance  in  the 
economy  of  Nature,  requiring  atmospheric  0  not  only  for  their 
work,  but  for  their  very  existence.  Minute  animalcules  (in- 
fusoria, water-fleas)  and  fish  aid  in  purifying  water  by  feeding 
on  nitrogenous  matter  in  sewage. 

All  sorts  of  household  filtering  apparatus  are  in  use. 
Among  these  may  be  mentioned  brick  partitions  in  cisterns, 
nests  of  asbestos,  charcoal  filters,  and  those  of  spongy  iron,  and 
silicated  and  manganous  carbon  blocks.  The  best  filters  prob- 
ably for  domestic  use  are  made  of  unglazed  porcelain  (bisque) 
or  fossil  clay  (compressed  kieselguhr).  The  pores  of  these  are 
so  minute  as  not  to  permit  IMC  passage  of  micro-organisms. 

Filters  must  be  cleansed  by  immersing  in  boiling  water 
every  day  or  two,  as  otherwise  the  germs  in  them  multiply  so 
rapidly  as  greatly  to  increase  the  dangers  of  pollution  that 
these  utensils  are  designed  to  prevent.  In  case  of  the  slightest 
doubt  as  to  the  purity  of  any  given  drinking-water,  the  only 
safety  lies  in  boiling  it. 

SANITARY  ANALYSIS   OF  WATER. 

The  examination  of  drinking-water  for  practical  hygienic 
purposes  is  accomplished  chiefly  by  chemic  tests:  that  is,  in- 
directly for  bacterial  contamination.  Bacteriologic  methods 
have  not  proved  of  much  service,  as  the  disease-germs  are  gen- 
erally in  so  relatively  small  numbers  as  often  to  evade  search, 
while  contamination  from  the  air  or  other  sources  may  invali- 
date the  observations.  The  micro-organisms  commonly  found 
in  stale  water  (algae,  cyclops,  amoebae,  rotiferae)  are  harmless 
in  themselves  except  as  entozoa.  Their  presence  in  large  num- 


314  SANITARY  CHEMISTRY. 

bers,  however,  points  to  an  attendant  pabulum  of  decomposing 
organic  matter. 

Color. — The  color  of  water  is  best  estimated  by  filling  a 
2-inch  glass  cylinder  (closed  at  each  end  with  a  disk  of  color- 
less glass)  with  the  water  and  holding  it  before  an  illuminated 
white  surface,  or  looking  down  through  the  column  on  a  piece 
of  white  paper  beneath. 

Reaction. — Water  is  normally  faintly  acid.  The  reaction 
is  tested  with  litmus,  phenol-phthalein  (bleached  by  C02)  or 
lacmoid  (blue  with  alkalies,  red  with  mineral  acids  or  ferric 
salts,  unaffected  by  C02). 

Total  Solids. — The  total  residue  left  on  evaporation  and 
drying  should  not  be  more  than  600  parts  per  million,  or  40 
grains  to  the  gallon,  though  the  amount  has  less  significance 
in  artesian  water  than  in  river-water.  This  sediment  is  ignited 
at  a  red  heat  and  weighed  again.  The  loss  in  weight  repre- 
sents organic  and  volatile  matters;  the  remainder,  mineral 
hardness.  The  said  loss  should  never  reach  to  50  per  cent. 
of  the  total  residue.  If  on  heating  the  first  residue  it  blackens 
or  fumes  or  smells  like  burning  horn,  we  may  be  certain  there 
is  an  excess  of  organic  matter  present. 

Hardness. — This  may  also  be  determined  by  means  of  a 
standard  soap  solution,  prepared  by  dissolving  10  gm.  of  Castile- 
soap  shavings  in  a  liter  of  alcohol  (60  per  cent.)  and  water  (40 
per  cent.).  Each  c.c.  of  the  solution  represents  1  mg.  of 
CaC03.  The  solution  is  added  little  by  little  to  100  c.c.  of 
the  water  to  be  tested  in  a  flask,  and  shaken.  The  addition 
is  continued  until  the  resulting  lather  remains  appreciable  for 
five  minutes,  and  the  degree  of  hardness  readily  noted  from 
the  number  of  c.c.  used.  When  water  contains  less  than  50 
parts  of  mineral  water  in  1,000,000,  it  is  said  to  be  soft;  when 
more  than  150,  hard.  The  hardness  of  rain-water  is  generally 
less  than  1/2  degree  (1/2  grain  per  gallon). 

Chlorids. — An  excess  of  chlorids  (more  than  5  parts  Cl  in 
100,000)  is  generally  (except  in  deep  water  or  rain-water)  an 
indication  of  the  presence  of  sewage,  particularly  in  localities 
at  some  distance  from  the  ocean  or  salt-water  lakes  or  wells. 
The  amount  of  these  salts  (NaCl  principally)  is  estimated  by 
means  of  a  standard  solution  of  AgN03  containing  4.8  gm.  of 
the  latter  to  a  liter  of  distilled  water: — 

AgNO,  _L_    Cl    _  4  8 
170      ~  35.4  —  4 

Each  c.c.  of  the  solution  is  equivalent  to  0.001  gm.  of  Cl,  or, 


ANALYSIS  OF  WATER.  315 

if  100  c.c.  of  water  be  utilized  for  the  test,  each  c.c.  of  the 
standard  solution  stands  for  1  part  of  Cl  in  100,000  of  water. 

Estimation  of  Chlorin.  —  Titrate  100  c.c.  of  water  with  standard 
AgNO3  solution,  using  K2CrO4  as  an  indicator.  AgNO3  combines  with  the 
chlorids  until  they  are  used  up,  and  then  with  the  chromate,  forming  the 
orange-red  chromate  of  silver.  The  reaction  is  at  an  end  when  the  red- 
dish color  becomes  permanent.  The  number  of  c.c.  used  of  the  standard 
solution  corresponds  to  the  parts  in  100,000  of  Cl. 

Phosphates.  —  Phosphates,  if  present,  are  determined  by 
slightly  acidulating  500  c.c.  of  water  with  HN03,  evaporating 

to  50  c.c.,  adding  a  few  drops  of  dilute  Fe2Cl6  and  then  slight 
excess  of  NH4OH,  filtering  and  dissolving  residue  in  a  little 
hot  dilute  HN03;  the  solution  is  evaporated,  if  need  be,  to  5 
c.c.,  and  to  this  2  c.c.  of  (NH4)2Mo04  is  added,  throwing  down 
a  yellow  ppt.  of  phosphomolybdate  of  ammonium.  More  than 
6  parts  of  phosphates  [calculated  as  Ca3(P04)2]  in  10,000,000 
of  water  should  be  regarded  with  suspicion.  Phosphatic  rock 
dissolved  by  water  is  pptd.  or  removed  by  micro-organisms. 

Organic  Matter.  —  Waters  showing  a  high  0-consuming 
power  are  generally  more  unwholesome  than  others  with  a  low 
affinity  for  0.  A  simple  test  for  the  0-consuming  power  of 
animal  and  vegetable  impurities  in  drinking-water  depends  on 
the  deoxidizing  and  decolorizing  effect  on  K2Mn208  of  organic 
products. 

Experiment.  —  To  a  test-tube  nearly  filled  with  water  add  2  per  cent. 
of  strong  H?S04  and  then  5  drops  of  K2Mn208  solution,  0.300  mg.  to  the 
liter  of  distilled  water.  Boil  for  we  minutes,  when,  if  the  purple  color 
all  disappears,  organic  matter  is  in  excess  of  sanitary  limits  (more  than 
3  parts  in  1,000,000). 

The  odors  sometimes  produced  by  heating  the  water  resi- 
due (burning  glue,  hair,  rancid  fats,  urine,  etc.)  should  give  rise 
to  grave  suspicion. 

Ammonia.  —  The  total  N  should  not  exceed  0.13  to  0.15 
part  in  1,000,000.  In  the  natural  decomposition  of  organic 
substances  by  the  0  and  saprophytes  of  the  ground  air  NH3  is 
one  of  the  first  products.  NH4  compounds  may  also  be  pro- 
duced by  reduction  of  nitrates  and  nitrites  in  presence  of  or- 
ganic matter,  especially  in  deep  wells. 

The  reagent  employed  in  testing  for  NH3  is  called  Nessler's 
solution,  and  is  an  alkaline  solution  of  HgI2  prepared  by  the 
reaction  between  KI  and  HgCl2  and  NaHO  (method  of  prepa- 
ration under  "Air").  This  reagent  gives  a  yellow  or  brown 
color  with  free  NH3,  the  depth  of  coloration  varying  with  the 
amount  of  this  gas  present. 


2HgI2  +  NH3  =  NHg2I  +  SHI 


316  SANITARY  CHEMISTRY. 

The  test  is  a  very  delicate  one,  showing,  it  is  said,  1  part 
of  NH3  in  100,000,000  of  water.  Albuminoid  ammonia,  or  that 
present  in  combination  in  undecomposed  organic  matter,  is 
separated  from  the  other  constituents  by  distilling  with  K2- 
Mn208  and  an  alkali. 

To  determine  the  N"  of  NH4  compounds  place  in  a  glass 
retort,  connected  with  a  Liebig  condenser  and  receiver,  200 
c.c.  of  distilled  water  and  10  c.c.  of  a  25-per-cent.  solution  of 
Na2C03,  and  distil  until  the  distillate  shows  no  reaction  with 
Nessler's  reagent.  Then  introduce  500  c.c.  of  the  water  under 
examination  and  continue  distillation  at  the  rate  of  about  50 
c.c.  every  ten  minutes.  Add  2  c.c.  of  Nessler's  reagent  to  each 
50  c.c.  of  the  distillate,  collected  separately,  and  compare  color 
(fully  developed  in  five  minutes)  with  that  of  pure  water  con- 
taining some  standard  NH4C1  solution  (0.382  gm.  dissolved  in 
100  c.c.  of  ammonia-free  water,  each  c.c.  being  diluted  for  use 


Fig.  46. — Cylinder  for  Nesslerization. 

with  99  c.c.  of  pure  water  —  1  c.c.  =  0.00001  gm.  N"),  to  which 
2  c.c.  of  the  Nessler  fluid  is  added. 

According  as  the  yellow-brown  color  of  the  standard  mixt- 
ure is  deeper  or  lighter  than  that  obtained  from  the  water 
tested,  other  comparison  liquids  are  prepared  containing  less 
or  more  NH4C1  until  the  colors  agree.  Successive  distillates  of 
50  c.c.  are  tested  in  the  same  way  until  no  reaction  occurs  on 
nesslerizing.  The  sum  of  c.c.  of  diluted  standard  NH4C1  re- 
quired in  making  the  color-balances  represents  the  number  of 
hundredths  of  milligrams  of  N"  in  the  "free  ammonia."  A  ppt. 
obtained  by  this  method  shows  an  excess  of  NH3  beyond  sani- 
tary safety. 

If  the  evolution  of  NH4OH  continues  and  increases  up  to 
the  fourth  or  fifth  distillate,  it  is  probably  due  to  the  decom- 
position of  urea  or  other  nitrogenous  substance,  in  which  event 
this  part  of  the  process  should  cease  and  the  next  step  (for 
albuminoid  ammonia)  be  taken. 


ANALYSIS  OF  WATER.  317 

By  "albuminoid  ammonia"  is  understood  the  N  of  com- 
pounds convertible  into  NH3  by  alkaline  potassium  perman- 
ganate (8  gm.  of  K2Mn208  and  200  gm.  of  KHO  dissolved  in 
a  liter  of  distilled  water,  boiled  until  one-fourth  is  evaporated, 
and  then  made  up  to  a  liter  with  ammonia-free  water).  The 
contents  of  the  retort  left  from  the  first  step  are  thrown  out, 
the  retort  rinsed  thoroughly,  200  c.c.  of  distilled  water  and  50 
c.c.  of  permanganate  solution  introduced,  and  the  mixture  dis- 
tilled down  to  about  100  c.c.,  nesslerizing  the  last  portion  of 
50  c.c.  to  make  sure  that  NH3  is  absent.  Then  add  500  c.c.  of 
the  water  under  examination  and  proceed  with  the  distillation 
and  nesslerizing  just  as  for  the  free  NH3  in  the  first  step.  The 
difference  between  the  free  NH3  of  the  first  process  and  the 
total  NH3  of  the  second  is  the  combined  or  albuminoid  NH3 
present  in  the  water. 

Ammonia-free  water  for  making  these  tests  is  prepared 
from  distilled  water,  which  often  reacts  with  the  Nessler  fluid, 
by  boiling  down  to  three-fourths  with  a  grain  of  Na2C03  to 
the  liter,  or  by  distilling  water  slightly  acidulated  with  H2S04. 
Great  care  should  be  taken  to  prevent  extraneous  contamina- 
tion, by  rinsing  thoroughly  all  the  apparatus  used. 

Nitrites  and  Nitrates.  —  The  next  step  in  the  breaking 
down  in  the  soil  of  organic  matters  into  simpler  substances  is 
the  conversion  of  NH3  first  into  nitrites  and  then  into  nitrates. 
These  changes  can  take  place  only  by  the  aid  of  the  nitrifying 
germs,  which  in  the  presence  of  mineral  matters  transform 
NH3  into  nitrites  and  nitrates  of  Na,  K,  and  other  metals  at 
hand:  salts  which  are  the  source  of  most  of  the  N  of  plant- 
structure. 

It  is  evident  that  nitrites  in  drinking-water  are  of  less 
serious  import  than  free  NH3,  and  that  nitrates  have  a  still  less 
serious  significance,  showing  less  recent  contamination.  Un- 
objectionable subsoil-water  from  cretaceous  strata  may  contain 
a  proportion  of  nitrates  inadmissible  in  the  case  of  river-water. 
Nitrites  are  sometimes  produced  by  reduction  of  nitrates  by 
recent  sewage,  by  metals,  cement,  or  new  brick-work.  They 
are  sometimes  present  in  rain-water,  and  in  deep  well-water 
from  lack  of  0  to  complete  oxidation.  The  total  amount  of 
N  in  nitrites  and  nitrates  should  not  exceed  1  part  in  1,000,000. 
Well-waters  sometimes  contain  considerable  mineral  matter 
and  suspended  organic  substance  with  but  little  or  no  nitrates, 
owing  to  a  destructive  fermentation. 

Test  for  Nitrites. — Add  1  c.c.  each  of  naphthylamin-hydrochlorate 
solution  (10  gm.  of  b.  naphthylamin  and  10  c.c.  concentrated  HC1,  with 
H2O  to  make  250  c.c.)  and  of  a  saturated  aqueous  solution  of  sulphanilic 


318  SANITARY  CHEMISTRY. 

acid  to  100  c.c.  of  the  water.  A  pink  or  red  color  shows  that  the  water 
contains  nitrites.  This  color,  however,  to  be  of  sanitary  significance, 
should  appear  within  a  very  few  minutes,  as  exposure  to  the  air  for  a 
longer  time  causes  a  similar  change,  owing  to  absorption  of  nitrites  from 
the  atmosphere. 

Test  for  Nitrates. — Evaporate  in  a  suitable  porcelain  dish  50  c.c. 
of  water  to  dryness,  finishing  the  process  over  the  water-bath.  Next  stir 
the  residue  thoroughly  with  1  c.c.  of  phenol-disulphonic  acid  (made  by 
mixing  3  gm.  of  phenol  with  37  gm.  of  H2SO4  and  heating  for  six  hours 
in  the  water-bath)  and  dilute  with  about  25  c.c.  of  water;  add  NH4OH 
in  excess  and  make  up  the  solution  to  50  c.c.  If  nitrates  are  present,  the 
yellow  ammonium  picrate  is  formed,  varying  in  intensity  with  the  amount 
present. 

C6H4OHS03H  +  HN03  =  C6H4OHN02  +  H2S04 

The  proportion  of  nitrates  can  be  estimated  by  comparing 
a  standard  KN"03  solution  (0.722  gm.  per  liter;  1  c.c.  =  0.0001 
N),  of  which  1  c.c.  is  evaporated  in  a  Pt  basin,  treated  as  above 
and  made  up  to  50  c.c. 

To  draw  deductions  in  slight  degrees  of  pollution  the  nor- 
mal standard  of  Cl,  NH3,  etc.,  in  the  natural  waters  of  the  dis- 
trict must  be  known.  The  proportion  of  Cl  in  uncontaminated 
waters  is  fairly  constant;  when  due  to  sewage  it  (and  nitrates) 
is  likely  to  undergo  marked  variations. 

To  distinguish  between  animal  and  vegetable  water-con- 
tamination is  a  difficult  matter.  If  the  excess  of  organic  matter 
is  accompanied  by  excess  of  total  solids,  Cl,  NH3,  nitrites,  and 
nitrates  (unless  these  have  entered  the  water  directly),  the 
source  of  pollution  is  generally  animal  filth  or  sewage;  when 
these  conditions  do  not  co-exist,  the  pollution  is  probably 
vegetable  in  origin.  Decomposing  nitrogenous  matter  yields 
NH3  more  rapidly  on  distilling  with  alkaline  potassium  per- 
manganate than  does  non-decomposing  matter.  Water  con- 
taining fermenting  vegetable  matter  is  colored  yellow  by 
boiling  with  Na2C03?  and  nesslerizing  the  distillate  gives  a 
greenish  tinge. 

POISONOUS  METALS. 

The  poisonous  metals  rarely  or  occasionally  found  in 
drinking-water,  include  Ba,  Cr  (dye-works),  Zn,  As,  Cu,  Pb 
(dissolved  by  soft  water  or  waters  containing  nitrites,  nitrates, 
or  excess  of  C02;  also  by  humic,  ulmic,  and  other  peaty  acids 
and  by  free  H2S04  formed  by  oxidation  of  iron  pyrites).  One- 
tenth  grain  of  Pb  to  the  gallon  may  produce  plumbism.  Mn, 
Fe  (more  than  3  or  4  parts  in  1,000,000),  and  Al  are  also  objec- 
tionable in  notable  quantities. 

Ba  is  determined  by  slightly  acidulating  with  HC1  and 


ADULTERANTS  AND  SOPHISTICANTS.  319 

adding  solution  of  CaS04.  Cr  is  found  by  evaporating  a  liter 
of  the  water  to  dryness  with  a  little  KN03  and  KC103  and  then 
fusing;  any  Cr  is  present  in  the  residue  as  chromate,  and  on 
taking  up  with  acid  water  gives  a  blue  color  with  H202. 

Zn  is  best  detected  by  adding  sufficient  NH4OH  to  render 
slightly  alkaline,  heating  to  boiling,  filtering,  and  treating  fil- 
trate with  a  few  drops  of  K4FeCy6.  Beinsch's  test  is  best  for 
As,  evaporating  a  liter  of  the  water  (rendered  slightly  alkaline 
with  Na2C03)  nearly  to  dryness  and  acidulating  with  strong 
HC1.  KSCN  gives  a  blood-red  color  with  ferric  salts,  or  with 
ferrous  after  boiling  with  a  few  drops  of  HN03.  H202  gives 
a  brown  ppt.  with  a  concentrated  water  containing  Mn. 

Pb  is  found  easily  by  adding  to  the  water  in  a  tall  glass 
cylinder  a  drop  of  NH4HS,  giving  a  brownish-black  ppt.  of  PbS, 
not  cleared  up  by  HC1  (distinction  from  Fe)  nor  by  KCN  (dis- 
tinction from  Cu).  The  presence  of  the  latter  metal  may  be 
confirmed  by  adding  K4FeCy6,  getting  a  mahogany-red  color. 
Water  should  not  be  drunk  if  it  contains  above  1/20  gr.  Pb  or 
Cu,  V4  gr.  Zn,  V2  gr.  Fe  per  gallon,  or  the  faintest  trace  of  As. 


ADULTERANTS  AND  SOPHISTICANTS. 

FOOD. 

The  pernicious  practice  of  food  adulteration  is  carried  on 
in  this  country  to  an  extent  not  tolerated  by  any  other  civil- 
ized nation.  While  many  of  the  additions  are  comparatively 
harmless  (sophistication),,  th^T  all  constitute  a  fraud  upon  the 
purchaser  and  consumer. 

Milk. — Antiseptic  agents  are  commonly  added  to  milk  to 
make  it  keep  longer.  The  ones  most  frequently  employed  are 
borax,  boric  acid,  salicylates,  and  especially  formalin  (freezine). 
The  main  objection  to  the  use  of  these  compounds  is  the  stale- 
ness  of  the  food  which  they  are  used  to  preserve.  Borax  and 
sodium  or  calcium  carbonate  increase  the  total  solids  of  the 
milk.  Condensed  milk  is  skimmed  milk  boiled  down  to  about 
a  third  and  fortified  with  cane-sugar.  "Evaporated  cream"  is 
made  from  whole  milk  similarly  condensed. 

Test  for  Formalin.— Add  a  few  drops  of  dilute  phenol  to  the  milk, 
and  pour  the  mixture  on  strong  H2SO4,  getting  a  bright-red  ring. 

Test  for  Salicylic  Acid. — Render  25  to  50  c.c.  of  sample  feebly  acid 
with  H2S04  and  shake  thoroughly  with  an  equal  volume  of  a  mixture  of 
equal  parts  of  ether  and  petroleum  spirit.  Allow  to  separate  in  a  funnel 
and  draw  off  the  solvent,  filter,  and  evaporate  gently.  The  needle-like 
crystals  of  salicylic  acid  dissolved  in  a  little  water  give  a  violet  color 
with 


320  SANITARY  CHEMISTRY. 

Test  for  Borax  and  Boric  Acid. — A  few  drops  of  the  sample  mixed 
with  a  drop  of  HC1  and  a  drop  of  strong  alcoholic  solution  of  turmeric 
are  evaporated  to  dryness  and  a  drop  of  NH4OH  added  to  the  residue,, 
giving  a  dull-green  stain.  Boric  acid  is  normally  present  in  wine. 

Skimming  milk  increases  the  sp.  gr.  and  diminishes  the 
cream.  Milk  which  has  been  both  skimmed  and  watered  may 
have  a  normal  sp.  gr.,  but  is  thin  and  blue.  The  bacteria 
(lactic  acid  bacillus  and  others)  in  badly  kept  milk  may  amount 
to  3,000,000  or  4,000,000  per  c.c.,  and  are  the  active  cause  of 
the  summer  complaint  of  infants.  Milk  is  also  very  liable  to 
bear  the  germs  of  enteric  and  scarlet  fevers,  diphtheria,  tuber- 
culosis, and  foot-and-mouth  disease;  also  the  mold  of  thrush 
(O'idium  alhicans).  The  best  preventives  of  milk-infection  are 
cleanliness  in  milking  and  in  the  care  of  cows,  and  keeping  the 
milk  on  ice  from  the  time  it  is  drawn  until  ready  to  be  used. 
Bacteria  may  be  filtered  out  to  a  considerable  degree  through 
cotton. 

Butter. — The  substitution  of  oleomargarin  for  butter  is 
readily  detected  by  the  marked  difference  in  volatile  fatty 
acids:  nearly  8  per  cent,  in  the  case  of  butter  and  only  about 
1/2  per  cent,  in  oleomargarin.  A  mixture  of  butter,  oleomar- 
garin, and  cocoa-nut  oil  may  have  the  same  proportions  of 
insoluble  acids  as  butter,  and  is  distinguished  by  the  oleore- 
fractometer.  The  sp.  gr.  of  butter  is  rarely  below  0.91;  of  beef- 
fat,  -never  above  0.9045.  The  m.p.  of  butter  is  from  86°  to 
94°  F.;  of  beef-fat,  rarely  above  82°  P. 

Test  for  Butter  (Leffmann). — Wash  a  300  c.c.  flask  thoroughly; 
rinse  with  alcohol,  then  ether;  dry  by  heating  in  water-oven,  cool,  and 
weigh.  Introduce  5.75  c.c.  of  the  sample  tested  by  means  of  a  pipet 
heated  to  about  60°,  and  after  fifteen  minutes  weigh  again.  Then  add 
20  c.c.  of  glycerol-soda  solution  (1  part  of  100-per-cent.  NaHO  solution 
with  9  parts  of  pure  glycerin)  and  heat  over  the  Bunsen  flame  until  com- 
plete saponification  takes  place  (in  about  fifteen  minutes).  Dissolve  the 
soap  in  135  c.c.  of  water,  gradually  added  with  shaking,  and  add  5  c.c. 
of  20-per-cent.,  by  volume,  H2S04;  drop  in  a  piece  of  pumice,  and  distil 
until  110  c.c.  have  been  collected.  If  the  distillate  is  not  clear,  it  should 
be  thoroughly  mixed  and  filtered,  and  100  c.c.  of  the  filtrate  taken. 
Standardize  with  decinormal  alkali  in  the  usual  way;  if  only  100  c.c.  of 
distillate  are  taken,  the  findings  should  be  increased  by  1/10.  A  blank 
experiment  should  be  made  to  determine  the  amount  of  standard  alkali 
required  for  the  materials  (seldom  above  0.5  c.c.  for  good  glycerol)* 
Five  gm.  of  butter  yields  a  distillate  requiring  from  24  to  34  c.c.  of  deci- 
normal alkali  to  neutralize;  commercial  oleomargarin  (usually  churned 
with  milk),  1  to  2  c.c.  of  the  alkali.  Butter-fat  is  readily  and  completely 
soluble  in  ether;  beef-fat  leaves  a  residue. 

Lard  is  much  adulterated  with  cotton-seed  oil  or  beef- 
stearin  and  excess  of  water.  "Compound  lard"  may  be  made 


ADULTERANTS  AND  SOPHISTICANTS.  321 

of   maize-,   sesame-,   and   pea-nut   oils.      "Butterine"   has   lard 
added  to  the  milk  and  oleomargarin-oil  before  churning. 

Cheese. — Cheese  is  "improved"  in  weight  by  lard,  oleo- 
margarin,  cotton-seed  oil,  and  skim-milk.  ZnS04  ("cheese- 
spice")  is  sometimes  used  to  prevent  heading  and  cracking. 
Cheese  is  colored  with  carrot-juice,  saffron,  yellow  ochre,  and 
ferruginous  earths;  it  is  flavored  with  sage  and  parsley.  An- 
natto,  turmeric,  and  yellow  azo  dyes  are  employed  to  give  a 
rich-yellow  color  to  milk,  butter,  and  cheese. 

Test  for  Annatto. — Coagulate  1  ounce  of  milk  with  a  few  drops  of 
HC,H3O2,  heat,  strain,  press  out  excess  of  liquid;  triturate  curd  in  a 
mortar  with  ether;  decant  ether  and  add  to  it  10  c.c.  of  a  1-per-cent. 
solution  of  NaHO,  shake  and  allow  to  separate;  pour  off  upper  layer 
into  a  porcelain  dish,  put  in  a  small  strip  of  filter-paper,  and  evaporate 
gently.  The  strip  is  colored  bulf  or  orange,  turning  pink  with  SnCl2. 

Meats.  —  Sausage-meats  are  often  colored  with  carmin, 
fuchsin,  eosin,  or  benzopurpurin.  Meats  are  preserved  ("em- 
balmed") and  improved  in  appearance  by  the  addition  of  KN03, 
NaCl,  sulphites,  salicylic  or  boric  acid,  and  a  little  coloring 
matter.  Beginning  putrefaction  may  be  detected  by  holding 
a  rod  dipped  in  a  mixture  of  1  c.c.  each  of  ether  and  HC1  and 
3  c.c.  of  alcohol,  over  the  suspected  matter,  producing  fumes 
of  NH4C1. 

Canned  Goods. — Tinned  meats  are  often  preserved  by  the 
aid  of  NaCl,  KN03,  and  boric  or  salicylic  acid.  Tinned  goods, 
especially  if  acid,  are  likely  to  become  contaminated  with  the 
tin  of  the  can  or  the  lead  of  the  solder.  Decayed  meats  act  as 
irritant  poisons,  giving  rise  y)  vomiting,  purging,  depression, 
and  frequently  a  scarlatiniform  erythema.  Fermented  canned 
vegetables  swell  out  the  ends  of  the  container,  giving  a  hollow 
sound  on  striking. 

Bread  and  Cake. — The  loss  of  weight  in  flour  on  heating 
over  the  water-bath  should  not  exceed  15  per  cent.;  nor  the 
ashes  2  per  cent.  Sophistication  with  potatoes  shows  increase 
of  water  and  an  alkaline  ash.  The  amount  of  water  in  bread 
should  not  generally  exceed  40  per  cent,  (up  to  50  per  cent, 
when  quite  fresh).  Alum  is  normally  present  in  flour  and  bread 
to  the  extent  of  6  to  10  grains  in  a  4-pound  loaf.  The  addition 
of  alum  makes  the  loaf  whiter  and  more  hygroscopic.  Its  pres- 
ence in  any  quantity  may  be  detected  by  pouring  a  fresh  in- 
fusion of  logwood  (made  with  distilled  water)  over  the  flour 
or  bread.  The  color  of  the  logwood  is  changed  to  lavender  or 
violet-gray. 

CuS04  is  sometimes  used  to  make  a  stale  or  damaged  sam- 
ple of  flour  look  white;  a  brown  color  is  imparted  to  a  thin 


322  SANITARY  CHEMISTRY. 

slice  of  such  bread  when  dipped  in  a  dilute  solution  of  K4- 
FeCy6.  Bread  is  also  adulterated  with  chalk,  gypsum,  pipe-clay, 
ZnS04,  magnesia,  bone-dust  or  bone-ash,  ammonia,  and  plaster 
of  Paris.  These  separate  by  sinking  when  flour  is  shaken  with 
chloroform.  The  gravest  contamination  of  flour  is  ergot.  This 
may  be  detected  by  shaking  2  gm.  of  flour  with  10  c.c.  of  70- 
per-cent.  alcohol  containing  5  per  cent,  of  HC1  and  allowing  to 
subside;  if  ergot  is  present,  the  supernatant  liquid  is  colored 
blood-red.  Liquor  potassae  gives  a  distinct  herring-like  odor 
(propylamin)  if  ergot  is  present. 

SnCl2  and  K2C03  are  sometimes  used  surreptitiously  to 
give  to  ginger-bread  the  color  imparted  by  honey  or  molasses. 
PbCr04  is  occasionally  resorted  to  for  coloring  cakes  yellow, 
but,  as  a  rule,  harmless  vegetable  colors  are  used  for  this  pur- 
pose. Baking-powders  are  commonly  adulterated  with  alum, 
ammonia,  sulphuric  acid,  and  ground  rock. 

Sugar  and  Molasses.  —  Glucose  is  used  largely  in  cheap 
syrups,  strained  honey,  and  to  dilute  brown  or  maple  sugar.  It 
is  best  determined  by  the  polarimeter,  and  often  contains  As 
from  impure  acids  used  in  its  manufacture.  Much  "mapleine" 
is  made  by  adding  extract  of  hickory-bark  to  sucrose  or  glucose 
syrup.  Dark  molasses  is  sometimes  bleached  by  Zn  dust  and 
Na2S03,  Zn  being  subsequently  removed  by  oxalic  acid.  SnCl2 
is  sometimes  used  to  give  a  bright-yellow  appearance  to  syrups. 
Granulated  and  loaf  sugars  often  contain  ultramarine  blue  to 
improve  the  color;  it  is  decomposed  by  HC1,  showing  the  blue 
color.  Jellies  and  jams  are  often  nothing  else  but  glucose  and 
starch  paste,  flavored  with  essential  oils.  If  honey  gives  a  ppt. 
when  treated  with  excess  of  alcohol,  the  dextrin  of  commercial 
glucose  is  present. 

Test  for  Saccharin  (TJsed  as  a  Preservative). — Extract  50  c.c.  of 
sample,  acidulated  with  25-per-cent.  H2SO4,  with  a  mixture  of  equal  parts 
of  ether  and  petroleum  spirit,  and  evaporate  solvent  at  a  gentle  heat. 
The  sweet  residue  is  heated  with  2  c.c.  of  saturated  NaHO  solution  until 
mass  fuses  for  one-half  hour,  when  saccharin  is  changed  to  salicylic  acid. 
If  the  latter  was  originally  present,  it  may  be  separated  by  dissolving 
the  ether  residue  in  50  c.c.  dilute  HC1,  adding  Br  water  in  excess,  shaking 
well,  and  filtering  off  the  brominated  salicylic  acid. 

Vinegar. — Pure  vinegar  (wine,  cider,  spirit,  malt)  should 
contain  between  5  and  6  per  cent,  of  acetic  acid  and  have  a  sp. 
gr.  of  1.008  to  1.018.  Mineral  acids  are  detected  by  adding  a 
solution  of  methyl  violet,  which  turns  blue  with  mineral,  but 
not  with  organic,  acids.  H2S04  is  also  detected  by  evaporating 
some  of  the  vinegar  with  a  little  cane-sugar  nearly  to  dryness, 
getting  a  black  color,  due  to  charring.  Fruit-stand  "cider" 


ADULTERANTS  AND  SOPHISTICANTS.  323 

usually  consists  of  a  weak  solution  of  cider-vinegar  flavored 
with  rose-water  and  sparingly  sweetened.  Pickles  are  generally 
brightened  in  color  with  chlorophyl  or  other  vegetable  colors, 
but  CuS04  is  occasionally  used.  This  may  be  easily  detected 
by  immersing  a  knife-blade  or  other  strip  of  metal  in  the 
liquid,  getting  a  red  coating  of  Cu. 

Confectionery. — Sweetmeats  are  colored  by  careful  heat- 
ing (yellow  and  brown)  or  by  saffron,  turmeric,  annatto,  cochi- 
neal, logwood,  and  chlorophyl.  A  very  weak  solution  of  eosin 
is  used  to  color  red,  fluorescein  and  auramin  for  yellow,  and 
malachite  for  green.  Other  colors  less  often  employed  are 
fuchsin,  Bismarck  brown,  and  ferric  hydroxid  (for  chocolates), 
verdigris,  chrome-yellow,  picric  acid,  and  gamboge.  Organic 
compounds  are  distinguished  by  being  soluble  in  alcohol  and 
bleached  by  NaClO.  To  detect  mineral  adulteration  (chalk, 
plaster  of  Paris,  sand,  clay)  incinerate  and  dissolve  the  ash  in 
dilute  HNO3  and  employ  the  ordinary  group  tests.  Fuchsin 
may  be  found  by  shaking  the  neutral  solution  with  a  mixture 
of  equal  parts  of  ether  and  amylic  alcohol,  which  are  colored 
red  or  pink  on  separating.  Potato-meal  is  sometimes  added  to 
candies. 

Coffee. — Roasted  coffee  floats  for  some  time  on  water,  while 
roasted  chicory  quickly  sinks.  Chicory  contains  considerable 
sugar,  and  hence  gives  a  darker  infusion  than  pure  coffee. 
Ground  coffee  is  further  sophisticated  with  cocoa-shells  and 
roasted  vegetables  and  cereals;  also,  it  is  said,  with  roasted 
horse-liver  flavored  with  caramel.  Imitation  coffee-beans  are 
made  by  special  machinery—irom  roasted  acorns,  burnt  sugar, 
chicory,  and  roast  horse-liver.  Chicory  is  revealed  microscopic- 
ally by  the  long  dotted  ducts  in  its  structure.  It  is  itself 
adulterated  with  colored  earths,  oak-bark,  and  sawdust. 

Tea. — This  is  greatly  adulterated  with  the  leaves  of  various 
trees  faced  with  plumbago,  Cu,  Fe,  and  with  catechu,  added 
for  its  astringent  effect.  Tea-leaves  are  sometimes  colored 
black  with  plumbago;  green  with  CuS04  and  Prussian  blue. 
Used  leaves  are  often  dried,  rolled,  and  resold.  Lie  tea  is  an 
imitation  made  of  dust  and  tea-sweepings,  along  with  minerals 
held  together  by  means  of  starch  or  gum;  it  is  broken  down 
by  boiling  water. 

Cocoa. — This  is  generally  adulterated  with  sugar  and  the 
cheaper  starches  to  cover  the  excess  of  fat  and  render  more 
palatable.  Chocolate  is  often  adulterated  with  ground  pea- 
nuts and  almond-meal. 

Wines. — Cheap  wines  are  made  largely  from  other  fruits 
than  the  grape,  especially  raisins.  Champagne  has  been  made 


324  SANITARY  CHEMISTRY. 

entirely  from  gooseberries  and  water.  Sulphurous  acid  is  often 
present  in  wines.,  from  sulphites  used  as  preservatives  or  from 
the  burning  of  S  to  disinfect  the  casks.  Pb  is  sometimes  found 
in  white  wines,  where  it  has  been  placed  to  sweeten  the  product. 
Red  wines  are  sometimes  decolorized  to  white  by  means  of 
charcoal.  Sulphate  of  lime  is  sometimes  used  to  improve  the 
color  of  cheap  wines  ("plastering"),  and  logwood,  alum,  sugar, 
and  added  ethers  are  common  adulterants. 

Beer. — The  bitter  taste  of  beer,  normally  due  to  hops,  is 
often  produced  by  picric  acid,  strychnin,  or  picrotoxin. 

Test  for  Picric  Acid. — Evaporate  Y2  to  1  liter  of  beer  to  dryness 
on  water-bath;  treat  with  alcohol,  filter,  and  evaporate  filtrate;  dissolve 
residue  in  boiling  water  and  evaporate  again;  extract  residue  with  ether, 
which  dissolves  the  acid  and  on  evaporation  leaves  it  as  yellow  needles 
giving  a  blood-red  color  with  KCN  (isopurpuric  acid). 

Basic  lead  acetate  and  a  little  ammonia  ppt.  all  the  bitter 
substance  of  hops,  but  not  of  strychnin  or  picrotoxin.  Added 
glycerin  is  detected  by  the  acrid  vapors  on  incinerating  a  residue 
of  beer  after  evaporation.  Other  common  adulterants  are  alum, 
H2S04,  cream  of  tartar,  potash,  calamus,  caraway,  coriander, 
copperas,  capsicum,  ginger,  quassia,  wormwood,  and  ground 
oyster-shells. 

Spirits.  —  Young  raw  whisky  contains  fusel-oil  (later 
changed  to  ethers),  the  odor  of  which  is  best  detected  by 
evaporating  slowly  on  the  water-bath.  Hanson  says  that  fusel- 
oil  with  other  adulterants  will  make  a  very  fair  whisky  for  5 
cents  a  gallon.  Acids  are  often  added  to  imitate  the  acid 
reaction  of  mellow  age  (due  to  acetic  and  a  trace  of  valeric). 
Added  ethers  may  be  detected  by  Molnar's  test,  which  consists 
in  evaporating  a  little  whisky  with  excess  of  KHO;  on  adding 
excess  of  H2S04  to  the  residue  the  volatile  acids,  with  charac- 
teristic odors,  are  liberated. 

So-called  gin  is  often  made  from  a  mixture  of  sugar, 
water,  cinnamon,  alum,  cream  of  tartar,  capsicum,  and  a  little 
alcohol. 

Condiments. — Ground  spices  are  very  commonly  adulter- 
ated with  cocoa-shells,  bran,  rolled  oats,  pease,  cornmeal,  buck- 
wheat, starch,  sawdust,  flour,  etc. 

Tobacco. — Among  the  adulterants  of  tobacco  we  find  hay, 
apple-parings,  corn-husks,  paper,  cabbage,  potato-leaves,  rhu- 
barb-leaves, endive,  elm,  beet-root,  dock,  sea-weed,  sawdust, 
copperas,  and  coal-dust. 


ADULTERANTS  AND  SOPHISTICANTS.  325 


DRUG  IMPURITIES. 

Arsenic  is  frequently  present  in  bismuth  salts.  Most  mer- 
curous  salts  contain  traces  of  the  corresponding  mercuric  salts. 
FeS2  is  often  found  in  reduced  iron;  H2S  is  evolved  on  treating 
with  acids.  Bromates  in  alkaline  bromids  liberate  free  Br  on 
adding  dilute  H2S04.  lodates  in  iodids  liberate  free  I  in  con- 
tact with  mineral  acids.  Bi  in  Hg  is  readily  detected  by  shak- 
ing Hg  in  a  test-tube,  when  the  Bi  separates  as  a  black  powder. 
Common  salt  commonly  contains  some  MgCl2.  Hypophosphites 
often  contain  an  excess  of  sulphates.  Cream  of  tartar  is  often 
adulterated  with  starch,  alum,  and  acid  calcium  phosphate; 
less  often  with  calcium  sulphate  and  potassium  acid  sulphate. 
The  best  baking-powders  should  yield  about  12  per  cent.,  by 
weight,  of  gas,  but  many  yield  much  less. 

Compound  spirit  of  ether  contains  a  little  free  H2S03. 
Gums  are  notoriously  impure,  often  containing  dirt,  sticks, 
bark,  and  pebbles.  Digitalis  is  often  substituted  by  mullein- 
leaves  and  elecampane-leaves;  saffron  with  calendula;  senna 
with  argels.  Spanish  saffron  is  increased  in  weight  by  coating 
the  stigmas  with  colored  CaC03.  "Venice  turpentine"  usually 
consists  of  a  mixture  of  resins  with  oil  of  turpentine;  "Bur- 
gundy pitch,"  of  melted  resin  and  fat,  with  sufficient  water  to 
render  turbid.  Balsam  copaibas  is  commonly  adulterated  with 
East-India  wood-oil  and  paraffin-  or  vaselin-  oil.  Essential  oils 
are  very  commonly  sophisticated:  oil  of  rose  with  Indian 
grass-oil.  Olive-oil  is  generally  adulterated  with  oil  of  cotton- 
seed, walnut,  sesame,  poppy,  rape,  or  pea-nut;  codliver-oil  with 
porpoise,  shark-liver,  and  other  cheap  fish-oils.  When  shaken 
in  a  test-tube  with  an  equal  volume  of  nitric  acid  pure  olive- 
oil  should  show  a  green  coloration;  cotton-seed,  a  red  color. 
Cacao-butter  is  adulterated  with  tallow,  lard,  stearic  acid, 
paraffin,  bees-wax,  and  cocoa-nut  and  arachis  oils.  Imitation 
bees-wax  is  sometimes  made  from  tallow  hardened  with  sper- 
maceti and  carefully  colored. 

All  crude  drugs  (especially  cinchona  and  cannabis  Indica) 
vary  greatly  in  the  content  of  active  principles.  A  purple  color 
is  produced  on  heating  powdered  cinchona  in  a  test-tube  if 
sufficient  alkaloids  are  present.  In  the  United  States  Pharma- 
copeia will  be  found  many  practical  tests  for  chemic  impuri- 
ties, both  qualitative  and  quantitative,  the  latter  being  chiefly 
volumetric  for  the  permissible  limit  of  impurities. 


326  SANITARY  CHEMISTRY. 


ANTISEPTICS  AND  DISINFECTANTS. 

A  disinfectant  or  germicide  is  "an  agent  capable  of  de- 
stroying the  infective  power  of  infectious  material":  that  is, 
specific  germs.  An  antiseptic  retards  or  arrests  bacterial 
growth  and  toxin  formation;  it  may  or  may  not  be  germicidal. 
A  deodorant  is  an  agent  that  absorbs  or  oxidizes  offensive 
odors;  it  is  rarely  germicidal. 

The  removal  of  any  and  every  kind  of  dirt  and  filth  is 
essential  to  the  proper  office  of  these  agents.  Since  perfect 
asepsis  is  impossible,  antisepsis  must  often  be  added  to  cleanli- 
ness. Disinfection,  in  general,  depends  upon  (1)  heat,  (2) 
oxidation,  (3)  sunlight  or  actinism,  (4)  reduction,  (5)  coagula- 
tion, and  (6)  direct  toxic  action  upon  bacteria. 

Of  all  disinfectants,  the  most  efficient  is  moist  heat,  to 
which,  at  the  temperature  of  boiling  water,  all  pathogenic  bac- 
teria and  their  spores  succumb  within  five  minutes.  For  ster- 
ilizing .instruments  for  an  operation  nothing  is  better  than 
boiling  them  for  at  least  five  minutes  in  pure  water,  to  which 
1  per  cent,  of  ]STa2C03  may  be  added  to  cleanse  adherent  grease 
and  prevent  rusting.  Gauze  and  other  dressings  should  be 
sterilized  by  steam  heat  just  previous  to  being  used.  Dry  heat 
is  not  nearly  so  effective  as  moist  heat,  and  when  necessary 
to  resort  to  this  method  it  should  be  applied  at  about  300° 
F.  and  fractionally, — that  is,  for  a  short  time  on  successive 
days, — in  order  to  destroy  any  spores  that  may  have  resisted 
the  heat  and  developed  into  germs. 

Acetanilid. — This  remedy  in  powdered  form  is  used  by 
many  physicians  as  a  local  antiseptic,  particularly  in  the  treat- 
ment of  chancroids.  Like  other  coal-tar  preparations,  it  may 
give  rise  to  depression  and  cyanosis. 

Acetylene. — This  gas,  freshly  generated  by  applying  CaC2 
to  moist  surfaces,  has  been  used  as  a  deodorant  in  cancer  of 
the  womb  and  similar  conditions. 

Alcohol. — The  antiseptic  properties  of  alcohol  depend  on 
its  dehydrating  and  coagulating  effects,  by  which  the  germs 
are  deprived  of  the  moisture  necessary  to  their  growth  and  are 
also  acted  upon  directly  as  to  their  waxy  capsules.  It  is  some- 
times used  as  an  intra-uterine  injection  in  cases  of  puerperal 
fever. 

Benzole  Acid. — This  acid  is  not  to  be  classed  as  a  ger- 
micide, but  has  sufficient  inhibitory  activity  (1  to  900)  to  pre- 
vent the  rancid  decomposition  of  animal  fats,  and  hence  is 
much  used  in  ointments.  Internally  in  doses  of  10  to  30  grains 


ANTISEPTICS  AND  DISINFECTANTS.  3£7 

benzole  acid  is  a  serviceable  antiseptic  remedy  in  chronic  cys- 
titis. 

Boric  Acid. — It  is  inhibitory  rather  than  germicidal.  A 
1  to  133  solution  arrests  the  activity  of  most  bacteria.  It  is 
free  from  irritating  or  toxic  qualities  and  from  disagreeable 
taste  or  odor.  A  saturated  solution  (4  per  cent.)  is  commonly 
employed  for  the  sterilization  of  mucous  surfaces,  and  is  a  good 
deodorizer  in  cases  of  fetid  perspiration.  A  1-per-cent.  lotion 
is  used  extensively  for  preventive  purposes  in  cleansing  the 
mouth,  nose,  and  eyes  of  infants  as  well  as  the  nipples  of  the 
mother.  Boric  acid  is  frequently  added  to  alkaloidal  solutions, 
to  forestall  decomposition.  Insufflations  of  the  dry  powder 
into  the  auditory  canal  after  cleansing  the  latter  are  generally 
rapidly  curative  in  suppuration  of  the  middle  ear. 

Borax  is  also  slightly  antiseptic,  and  in  saturated  solution 
(12  per  cent.)  has  yielded  good  results  in  the  various  forms  of 
tinea.  The  glycerite  of  boroglycerin  is  made  some  use  of  as 
an  antiseptic  vehicle  for  alkaloids  and  glucosids  in  the  local 
treatment  of  skin  and  eye  diseases. 

Bromin. — Like  the  other  members  of  the  halogen  group, 
this  element  is  a  disinfectant  and  deodorizer  of  great  power. 
Over  6000  pounds  of  Br  were  used  at  Johnstown,  Pa.,  after 
the  great  flood  in  1889.  The  highly  corrosive  nature  of  the 
liquid  and  the  irritating  character  of  the  fumes  which  it  evolves 
make  its  employment  out  of  the  question  in  the  operating-room 
and  in  the  sick-chamber.  The  bromids  are  also  antiseptic, 
NaBr  in  10-per-cent.  solution  being  destructive  to  the  germs 
of  cholera  and  typhoid. 

Carbolic  Acid. — The  disinfectant  properties  of  phenol  were 
first  recognized  by  Chaumette  in  1815,  but  it  was  not  until 
1867  that  the  new  era  of  surgery  was  inaugurated  by  Lister  in 
his  memorable  communication  on  the  merits  of  this  drug.  The 
disinfectant  potency  of  phenol  is  well  established.  Generally 
speaking,  we  may  be  certain  of  reliable  antiseptic  results  with 
a  5-per-cent.  solution  of  the  acid.  In  this  strength  it  is  much 
employed  to  sterilize  instruments,  particularly  those  that  would 
be  injured  by  heat.  According  to  Yersin,  a  1-per-cent.  solution 
will  destroy  tubercular  bacilli  in  one  minute.  Carbolates  and 
sulphocarbolates  are  much  weaker. 

Carbolic  acid  coagulates  albumin  with  facility.  It  can  act 
in  the  presence  of  sebaceous  and  oily  matters.  It  is  an  effective 
local  anesthetic,  and  is  sufficiently  soluble  in  the  common  solv- 
ents. The  chief  objection  to  carbolic  acid  is  liability  to  sys- 
temic poisoning,  manifested  by  smoky  urine,  pain  in  the  lumbar 
region,  dyspnea,  and  possibly  collapse.  It  also  benumbs  and 


328  SANITARY  CHEMISTRY. 

corrodes  the  hands  and  dulls  the  instruments  of  the  operator. 
The  former  use  of  the  carbolic  spray  during  operations  rested 
on  the  faulty  supposition  that  infection  took  place  through  the 
atmosphere  rather  than  by  way  of  the  hands,  dressings,  and 
instruments.  The  attempts  at  disinfection  of  a  sick-room  with 
vapors  of  carbolic  acid  or  similar  compounds  are  equally  illog- 
ical and  futile. 

Chloral  Hydrate. — A  5-per-cent.  lotion  has  been  used  with 
satisfaction  in  the  treatment  of  foul  ulcers  and  parasitic  skin 
affections.  It  is  also  employed  as  a  deodorant  in  the  urinals 
of  paralytic  patients. 

Chlorin. — The  disinfectant  value  of  this  element  has  been 
recognized  since  its  discovery  by  Scheele  in  1774.  It  has  a 
great  affinity  for  H,  which  it  takes  from  H20,  setting  free  the 
powerful  germicide  nascent  0.  Hence  the  necessity  for  moist- 
ure in  the  use  of  this  agent.  Cl  also  acts  as  a  deodorizer  by 
taking  away  the  H  of  sewer-gas.  Nissen  determined  that  a 
solution  of  1/2-  to  1-per-cent.  strength  destroys  the  germs  of 
typhoid  and  of  cholera  within  five  minutes. 

Cl  for  disinfecting  purposes  is  derived  almost  exclusively 
from  calx  chlorata,  the  so-called  chlorid  of  lime,  which  evolves 
the  gas  gradually  in  the  presence  of  moisture.  It  should  con- 
tain at  least  25  per  cent,  of  available  Cl.  Chlorinated  lime  is 
altogether  the  most  suitable  substance  for  deodorizing  drains, 
sinks,  and  water-closets,  and  for  disinfecting  alvine  evacuations 
and  other  discharges.  For  the  latter  purpose  the  fresh  powder 
should  be  used  in  the  proportion  of  a  half-pound  to  the  gallon. 
It  ought  always  to  be  placed  in  the  vessel  before  depositing 
the  excretions  therein. 

Common  salt  and  ZnCl2  are  inimical  to  all  low  forms  of 
life.  Of  the  former,  a  saturated  solution,  says  Miquel,  will  kill 
cholera  spirilla  in  a  few  minutes.  The  latter  compound  is  anti- 
septic in  the  strength  of  1  to  25.  A  10-per-cent.  lotion  is  a 
serviceable  caustic  application  for  foul  ulcers. 

Chloroform.  —  This  well-known  anesthetic  prevents  fer- 
mentation due  to  micro-organisms,  while  it  does  not  impede 
the  function  of  the  unorganized  digestive  ferments.  Water 
and  spirit  of  chloroform  are  therefore  efficacious  remedies  in 
digestive  disorders  attended  with  fermentation  and  flatulence. 

Chromic  Trioxid.  —  Koch  asserts  that  Cr03  is  markedly 
germicidal,  and  Miquel  claims  that  it  is  antiseptic  in  a  1  to 
5000  solution.  The  drug  is,  however,  very  irritating  and 
caustic,  and  death  has  ensued  from  its  too  free  application. 

Citric  Acid. — A  solution  1  to  200  in  strength  will  kill  the 
spirilla  of  cholera  on  a  half-hour's  exposure;  hence  the  benefits 


ANTISEPTICS  AND  DISINFECTANTS.  399 

from  drinking  lemonade  in  times  of  cholera  and  other  water- 
borne  infections. 

Copper  Sulphate.  —  In  5-per-cent.  solutions  this  salt  is  a 
powerful  disinfectant  (coagulates  albumin)  and  an  absorbent 
of  H2S  and  ammonias. 

Creasote. — Beech-wood  creasote,  in  spite  of  its  irritating 
properties,  is  still  widely  employed  as  an  intestinal  antifer- 
mentative  and  digestive  stimulant,  particularly  in  tuberculous 
cases.  Creasote  is  related  to  phenol,  and  is  apt,  when  used  in 
excess,  to  produce  analogous  symptoms  of  systemic  poisoning, 
such  as  headache,  stupor,  and  smoky  urine.  Schill  and  Fisher 
found  that  a  1-per-cent.  solution  of  creasote  failed  in  twenty- 
four  hours  to  kill  the  tubercle  bacillus. 

Creolin. — A  2-  to  5-per-cent.  emulsion  with  water  is  some- 
times used  for  vaginal  injections,  and  stronger  mixtures  are 
employed  for  general  disinfection.  Lysol  is  a  similar  mixture 
of  cresols,  and  is  freely  soluble  in  water. 

Cyanid  of  Zinc  and  Mercury. — This  insoluble  compound 
has  been  used  to  some  extent  in  the  form  of  gauze  for  surgical 
dressings.  It  is  feebly  germicidal,  strongly  antiseptic,  and  non- 
irritating,  but  extremely  poisonous,  on  which  account  its  use 
should  be  condemned. 

Ether. — Ethylic  ether  in  full  strength  is  an  efficient  ger- 
micide. Its  chief  use  in  surgery,  however,  aside  from  anesthe- 
sia, is  to  dissolve  and  remove  the  fatty  matters  of  the  skin 
before  applying  antiseptic  solutions.  It  is  employed  for  the 
same  purpose  in  the  preparation  of  surgeon's  catgut. 

Eucalyptol. — This  is  a  camphor-like  substance  credited  by 
Behring  with  an  antiseptic  potency  one-fourth  that  of  carbolic 
acid.  The  eucalyptus  preparations  are  indicated  in  chronic 
urinary  diseases  associated  with  decomposition  of  urine  within 
the  body. 

Ferrous  Sulphate. — Copperas  is  not  a  germicide,  but  has 
weak  antiseptic  properties  and  in  strong  solutions  is  of  service 
as  a  deodorizer  for  vaults  and  other  damp  places. 

Formaldehyd. — The  marked  efficiency  of  this  gas  was  dis- 
covered by  Trillat  and  Aronson  in  1892.  A  1-per-cent.  solution 
destroys  nearly  all  germs  in  less  than  thirty  minutes.  The  gas 
is  an  admirable  surface  disinfectant,  but  has  not  the  penetrating 
power  of  S02.  Its  germicidal  power  is  probably  due  to  the  fact 
that  it  renders  albuminoids  insoluble  in  water. 

For  disinfecting  rooms  the  gas  may  be  produced  by  heat- 
ing solid  paraformaldehyd  over  an  alcohol-lamp;  or  it  can  be 
developed  directly  by  oxidation  of  methyl  alcohol,  the  vapors 
of  which  are  made  to  pass  through  heated  metal  tubes  or  coils. 


330  SANITARY  CHEMISTRY. 

Another  method,  recommended  by  Novy,  is  to  heat  formalin 
(40-per-cent.  aqueous  solution)  containing  10  per  cent,  of  glyc- 
erin or  a  little  CaCl2  (dehydrates  gas);  or  by  dipping  sheets 
in  a  weak  formalin  solution  and  hanging  them  upon  lines  in 
the  room.  As  HCOH  is  quite  diffusible,  all  apertures  of  the 
room  should  be  kept  tightly  closed  for  six  or  eight  hours  while 
the  gas  is  operating.  Its  irritating  odor  is  quickly  dispelled  by 
evaporating  some  NH4OH  in  the  room.  For  thorough  disin- 
fection it  is  well  also  to  wash  the  furniture  with  antiseptic 
solutions,  to  rub  the  wall  with  bread-crumbs,  to  scrub  the  floor 
thoroughly,  and  to  boil  all  the  clothes  and  bedding  that  can 
be  treated  in  this  way. 

For  surgical  use  formaldehyd  is  utilized  in  1/4-  to  1/2-per- 
cent.  solutions;  for  general  antisepsis,  Y2-  to  2-per-cent.  solu- 
tions; and  for  sterilizing  catgut,  a  4-per-cent.  solution.  Like 
HgCl2,  formalin  roughens  and  hardens  the  hands.  Paraform 
pastils  are  very  convenient  for  sterilizing  catheters  by  keeping 
them  together  in  a  closed  box. 

Glycerin. — Copeman  discovered  in  1891  that  glycerin  is 
able  to  sterilize  vaccine  pulp  sufficiently  for  clinical  purposes, 
without  affecting  the  properties  of  the  unknown  vaccinia  germ, 
and  glycerinated  lymph,  preserved  in  sterile  capillary  tubes,  is 
at  present  the  most  convenient  and  acceptable  form  of  vaccine. 

lodoform. — The  clinic  benefits  accruing  from  the  applica- 
tion of  CHI3  depend  mainly  on  starving  the  germs  by  absorp- 
tion of  local  secretions  and  on  chemic  changes  in  the  toxins. 
In  the  presence  of  much  moisture  free  I  is  also  evolved,  and 
aids  in  the  approximate  sterilization  of  the  tissues.  Some 
micro-organisms  grow  in  iodoform,  and  prudence  dictates  that 
the  drug  should  be  itself  sterilized  by  heat  before  using  it.  A 
10-per-cent.  solution  in  olive-oil  is  especially  valuable  for  in- 
jection in  tubercular  affections  of  the  joints. 

The  immoderate  use  of  iodoform  as  an  application  to  fresh 
wounds  is  a  matter  to  be  deprecated,  since  alarming  toxic  symp- 
toms may  follow:  such  as  erythema  or  eczema;  headache;  faint- 
ness;  prostration;  high  fever;  rapid,  feeble  pulse;  amblyopia; 
and  cerebral  phases  simulating  meningitis.  Elderly  persons 
are  especially  susceptible  to  the  deleterious  influence  of  the 
drug.  The  invincible  odor  of  CHI3  is  very  offensive  to  sensitive 
patients.  Of  the  many  iodoform  substitutes,  iodol  is  probably 
best. 

Lactic  Acid.  —  Although  the  product  of  alimentary  fer- 
mentation, this  acid,  in  larger  quantity,  inhibits  fermentative 
changes.  Kitasato  states  that  a  4  to  1000  solution  is  destruc- 
tive to  typhoid  bacilli. 


ANTISEPTICS  AND  DISINFECTANTS.  331 

Lime. — Fresh  CaO  is  a  strong  germicide,  1  to  1000  being 
sufficient  to  destroy  cholera  and  typhoid  germs.  It  is  used 
mainly  for  disinfecting  manure-heaps  and  privy-ordure. 

Mercuric  Chlorid. — The  reign  of  corrosive  sublimate  as  an 
antiseptic  began  in  1881,  when  Koch  affirmed  its  generally 
germicidal  action  in  solutions  as  weak  as  1  to  15,000.  A  1  to 
1000  solution  is  needed  for  non-spore-bearing  bacteria;  1  to 
500  for  the  spore-bearers.  Abbott  has  ascertained  that  a  1 
to  500  solution  will  not  destroy  pus-cocci  even  in  the  absence 
of  spores.  It  has  been  demonstrated  by  a  number  of  observers 
that  the  action  of  strong  solutions  of  HgCl2  is  not  germicidal, 
but  inhibitory,  and  that  when  the  chemical  is  pptd.  from  the 
germs  they  again  resume  their  vital  functions. 

The  principal  objections  to  the  use  of  HgCl2  as  an  anti- 
septic are  as  follows:  It  is  irritating  to  the  tissues,  even  causing 
necrosis.  Strong  solutions  roughen  the  hands.  If  absorbed  to 
the  extent  of  a  grain  or  more,  it  is  apt  to  produce  alarming 
toxic  symptoms.  It  combines  with  albumin,  forming  an  in- 
soluble and  inert  (while  undissolved)  compound;  nor  can  it 
act  in  the  presence  of  fat  or  soap.  In  aqueous  solution  it  is 
quite  unstable,  tending  to  reduction  into  calomel.  It  is  very 
corrosive  to  instruments.  Despite  the  above  disadvantages, 
HgCl2  remains  the  favorite  antiseptic  of  a  large  proportion  of 
physicians  and  surgeons.  That  such  should  be  the  case  shows 
merely  that  a  dictum,  once  established,  is  difficult  to  overthrow. 

Methylene  Blue.  —  This  is  a  valuable  urinary  antiseptic 
when  given  by  the  mouth.  It  colors  the  urine  blue  or  green. 
The  conjoint  administration  of  spices  prevents  gastric  irrita- 
tion. 

Mineral  Acids. — Hydrochloric,  nitric,  and  sulphuric  acids 
have  each  slight  antiseptic  energy.  The  first  named  has  sup- 
planted lactic  acid  in  the  treatment  of  ordinary  stomachic  in- 
digestion. 

Mustard. — A  solution  of  the  oil  of  black  mustard  only 
1  to  33,000  is  capable  of  preventing  the  development  of  an- 
thrax-spores. All  the  essential  oils  have  more  or  less  antiseptic 
power. 

Naphtalin.  —  Naphthalene  is  utilized  as  a  prophylactic 
against  moths.  Betanaphtol  is  sometimes  administered^  as  an 
intestinal  antiseptic.  It  is  liable  to  be  contaminated  with  its 
poisonous  isomer,  alphanaphtol.  The  derivative  hydronaphtol 
is  also  prescribed  as  an  intestinal  disinfectant. 

Oxygen. — Despite  the  popular  belief  to  the  contrary,  ordi- 
nary molecular  0  is  not  directly  germicidal  except  in  the  case 
of  the  relatively  rare  anaerobic  bacteria.  It  is  the  freshly  lib- 


332  SANITARY  CHEMISTRY. 

erated  or  nascent  atomic  form  of  the  gas  which  is  a  true  and 
powerful  germicide.  Whatever  merits  ozone  may  possess  as  a 
disinfectant  are  due  to  breaking  up  of  the  gas  into  nascent  0 
and  the  ordinary  form.  The  good  effects  derived  from  the  use 
of  wood-charcoal  in  fermentative  disorders  depend  largely,  no 
doubt,  on  the  0  occluded  in  its  pores,  as  well  as  on  absorption 
of  the  abnormal  gaseous  products. 

Peroxid  of  Hydrogen. — This  is  likewise  an  oxidizant,  lib- 
erating free  0  (ordinarily  about  10  volumes)  in  the  presence 
of  all  kinds  of  organic  matter.  It  seems  to  have  a  special 
affinity  for  pus,  and  may  be  used  to  detect  the  presence  of  a 
purulent  secretion  in  a  cavity,  by  the  effervescence  which  en- 
sues on  injecting  the  fluid.  The  principal  objection  to  the 
remedy  is  its  instability  and  the  consequent  uncertainty  of  each 
specimen.  Other  disadvantages  are  its  corrosive  action  upon 
metals  and  the  danger  of  explosion  of  the  confined  fluid  when 
heated. 

Petroleum. — Crude  petroleum  and  kerosene  have  come  into 
extensive  use  of  late  for  destroying  the  larvae  of  yellow-fever- 
and  malaria-  bearing  mosquitoes.  The  oil  is  spread  on  the  sur- 
face of  pools  infested  by  these  insects. 

Potassium  Permanganate.  —  This  is  an  efficient  oxidizing 
germicide.  The  tubercle  bacillus  is  the  only  common  pathog- 
enic germ  which  withstands  the  action  of  a  5-per-cent.  solu- 
tion. The  drug  is  not  adapted  to  internal  administration,  since 
it  is  quite  irritating  to  the  stomach;  in  the  presence  of  readily 
combustible  substances  it  has  sometimes  exploded.  According 
to  Weir  Mitchell,  it  is  the  most  efficacious  local  antidote  for 
snake-bite. 

K2Mn2Os  has  of  late  years  risen  to  prominence  as  a  dis- 
infectant for  the  surgeon's  hands.  The  method,  introduced  by 
Kelly,  consists  of  three  steps:  first,  scrubbing  the  arms,  hands, 
and  nails  thoroughly  with  soap  and  hot  water;  second,  immer- 
sion of  the  parts  in  a  saturated  solution  of  permanganate; 
third,  washing  off  the  K  salt  with  a  saturated  aqueous  solution 
of  oxalic  acid  until  the  purple  color  has  all  been  removed. 
Oxalic  acid  itself  is  a  strong  antiseptic,  and  so  reinforces  the 
action  of  the  permanganate.  The  resulting  itching  of  the  skin, 
if  annoying,  may  be  relieved  by  bathing  with  sterilized  lime- 
water,  also  an  antiseptic. 

Quinin. — The  salts  of  quinin  have  a  special  destructive 
predilection  for  the  Plasmodium  malarice,  even  in  as  weak  solu- 
tion as  1  to  20,000.  The  sulphate  is  generally  antiseptic  in  the 
strength  of  1  to  800;  the  hydrochlorate,  1  to  900. 


ANTISEPTICS  AND  DISINFECTANTS.  333 

Resorcin. — This  benzene  derivative  has  come  into  promi- 
nence as  a  gastro-intestinal  antiseptic  and  as  an  ingredient 
of  soaps  and  ointments  for  parasitic  and  scaly  skin  diseases. 
Large  doses,  Y2  dram  or  more,  induce  the  symptoms  of  de- 
pression characteristic  of  phenol  compounds. 

Salicylic  Acid. — According  to  Miquel,  this  product  is  anti- 
septic in  the  strength  of  1  to  1000.  Its  unquestioned  efficacy 
in  rheumatism  probably  depends  on  its  antiseptic  properties. 
It  is  not  a  good  dressing  for  wounds,  since  it  irritates  and 
macerates  the  tissues  and  does  not  stay  in  place.  The  internal 
administration  of  the  acid  made  from  phenol,  particularly,  may 
cause  roaring  in  the  ears,  headache,  delirium,  and  erythema; 
48  grains  taken  within  four  hours  have  produced  death  in  an 
adult. 

Salol. — The  salicylate  of  phenol  is  broken  up  by  the  pan- 
creatic juice  into  carbolic  and  salicylic  acids.  It  has  been  used 
extensively  for  infectious  intestinal  diseases  and  even  for  chol- 
era, but  Eeiche  states  that  in  the  Hamburg  epidemic  of  1892 
salol  was  an  utter  failure.  Salophen  and  aspirin  seem  to  possess 
all  the  advantages  of  salol  and  ealicylates  without  any  of  their 
objectionable  features. 

Silver  Nitrate.  —  This  well-known  compound  has  been 
rated  by  Behring  next  to  HgCl2  in  antiseptic  potency.  It  can 
be  utilized  in  nearly  all  inflammatory  and  ulcerative  states  of 
the  mucous  membrane.  Perhaps  its  most  noteworthy  applica- 
tion is  in  ophthalmia  neonatorum.  The  use  of  AgN03  as  an 
antiseptic  is  limited  by  the  discoloration  of  the  tissues  which 
it  produces,  its  neutralization  by  NaCI  in  the  secretions,  and 
the  possible  dangers  of  argyria.  There  are  many  excellent  sub- 
stitutes for  AgN03,  protargol  being  probably  the  best. 

Soap.  —  According  to  Parkes,  ordinary  soap  possesses 
marked  disinfectant  properties.  He  adds  that  there  is  little 
or  no  advantage  in  using  soaps  impregnated  with  small  quan- 
tities of  disinfectants. 

.  Sulphurous  Acid. — The  gas,  S02,  produced  by  the  burning 
of  S,  unites  with  aqueous  vapor  to  form  the  strongly  germicidal 
H2S03.  The  dry  gas  is  but  feebly  destructive  of  germs;  hence 
the  necessity  of  placing  the  sulphur  dish  in  a  vessel  of  water. 
The  H2S03  thus  produced  kills  the  bacillus  of  anthrax  in  5- 
per-cent.  solution  or  non-spore-bearers  in  1-per-cent.  solution 
within  twenty-four  hours.  For  fumigation  three  pounds  of  S  are 
required  for  each  thousand  cubic  feet  of  space.  The  fumigation 
should  last  at  least  twelve  hours,  with  doors  and  windows  closed 
and  the  cracks  well  stuffed  with  cotton. 


334  SANITARY  CHEMISTRY. 

Tannic  Acid. — In  addition  to  its  valuable  astringent  prop- 
erties, Abbott  has  found  that  this  drug  is  antiseptic  in  solutions 
of  1  to  400. 

Thymol. — This  stearopten  has  one-fourth  '  the  antiseptic 
potency  of  carbolic  acid.  It  is  used  for  respiratory  affections 
in  the  form  of  sprays  or  inhalations,  and  externally  in  oint- 
ments for  scaly  skin  diseases.  Thymol  has  a  pleasant  odor, 
attractive  to  flies,  unfortunately. 

Turpentine.  —  The  oil  of  turpentine  and  its  derivatives, 
terebene  and  terpin  hydrate,  are  of  some  power  as  antiseptic 
agents,  but  are  too  irritating  for  surgical  ends,  as  a  rule.  Tur- 
pentine, in  conjunction  with  tincture  of  iodin,  is  a  very  valu- 
able application  for  ringworm. 

Urotropin. — Hexamethylentetramin  is  a  valuable  urinary 
antiseptic,  especially  after  typhoid  fever.  It  liberates  formal- 
dehyd  in  the  urinary  passages. 

Vinegar. — Klein  and  McClintock  agree  that  dilute  acetic 
acid  (7  per  cent.)  is  as  efficient  in  preventing  the  growth  of 
micro-organisms  as  is  a  1  to  1000  solution  of  HgCl2.  Kitasato 
found  that  a  3-per-cent.  solution  of  the  acid  kills  typhoid  ba- 
cilli in  five  hours.  Acids  generally  are  inimical  to  germ-life. 

v 

QUESTIONS  ON  SANITARY  CHEMISTRY. 

1.  Explain  darkening  of  permanganate   solution  in  the  presence 
of  reducing  agents. 

2.  How  detect  Na2CO3  in  residue  from  evaporated  milk? 

3.  What  is  formed  when  NH3  combines  with  HCOH  after  disin- 
fecting a  sick-room? 

4.  Name  five  oxidizing  disinfectants. 

5.  What  are  the  final  products  of  the  oxidation  of  organic  matter? 
*6.  Name  two  reducing  disinfectants. 

7.  Name  three  coagulating  disinfectants. 

8.  Name  an  oxidizing  and  an  absorbing  deodorizer. 

9.  How  remove  acidity  due  to  C02  from  water? 

10.  How  does  pumping  considerably  from  a  farm-well  increase  the 
amount  of  impurities  in  the  water? 

11.  How  does  agitation  with  iron  filings  purify  drinking-water? 

12.  Why  is  deep  well  water  harder  than  rain  water? 

13.  Why  is  soft  water  better  than  hard  for  boiling  meat  and  vege- 
tables? 

14.  Are  plants  in  sleeping-rooms  healthful  or  not? 

15.  To  test  the  air  of  a  certain  room  quantitatively  for  C02,  if  the 
flask  is  brought  from  without  the  room,  how  can  you  empty  the  air 
already  in  it  and  fill  it  with  the  air  of  the  apartment  to  be  tested? 

16.  What  is  the  yellowish  color  produced  by  nesslerizing? 

17.  Why  should  all  cellars  be  cemented? 

18.  With   a   blotting-paper  and   suitable   reagents  how  could   you 
prove  the  presence  in  the  air  of  NH3,  H,S,  ozone,  SOj,  or  Cl? 


QUESTIONS.  335 

19.  Why  is  the  presence  of  NH4  compounds  in  deep  water  of  less 
serious  significance  than  in  surface-  or  subsoil-  waters? 

20.  How  prove  the  presence  of  alum  in  a  baking-powder? 

21.  Explain  the  corrosive  effect  of  HgCl2  on  surgical  instruments. 

22.  How  much  carbolic  acid  is  needed  to  disinfect  a  pint  of  tuber- 
culous sputum? 

23.  How    often    should    the    air    be    changed    in    a    sleeping-room 
12x14x8,  occupied  by  man,  wife,  and  child? 

24.  Describe  the  changes  which  organic  matter  undergoes  in  the  soil. 

25.  Write  equation  for  the  reaction  between  oxalic  acid  and  potas- 
sium permanganate. 

26.  What  objection  to  throwing  much  chlorinated  lime  down  drains? 

27.  The  pharmacopeial  limit   of  K2C03  in  KBr  is  0.138  per  cent. 
Directions  are  given  to  add  to  1  gm.  of  the  salt  in  10  c.c.  of  water  0.02 
c.c.  of  normal  H2S04,  after  which  phenol-phthalein  should  give  no  color 
unless  the  carbonate  is  in  excess.    Give  reasons. 


| 


TOXICOLOGY. 


DEFINITION. 

To  DEFINE  a  poison  is  about  as  difficult  as  to  explain  the 
signification  of  a  weed.  All  medicines  of  any  strength  what- 
ever may  produce  toxic  effects;  in  fact,  with  the  ancient  Greeks 
the  same  word  was  used  to  express  both  a  poison  and  a  medi- 
cine. A  pound  of  common  salt,  taken  for  tapeworm,  has  caused 
death  by  its  paralyzing  effect  upon  the  nervous  system.  Per- 
haps the  best  definition  of  a  poison,  then,  is  any  substance 
which  acts  injuriously  within  and  upon  the  human  body,  and 
is  capable  of  causing  death  in  a  way  not  merely  mechanic. 
Thus  an  injury  or  boiling  water  or  steam  may  prove  fatal,  but, 
being  mechanic  in  nature,  they  should  not  be  classed  as  poisons. 


ACUTE     POISONING. 

Poisons  may  be  introduced  into  the  body  by  the  mouth, 
lungs,  rectum,  vagina,  skin,  or  by  hypodermic  or  intravenous 
injection.  Toxic  agents  that  are  most  soluble  and  diffusible 
are  most  rapidly  fatal,  especially  when  inhaled  or  injected  in- 
travenously. Insoluble  substances  have  no  action  on  the  sys- 
tem until  they  have  been  more  or  less  dissolved  by  the  digestive 
secretions.  A  few  poisons  (curare,  snake-venom,  and  the  virus 
of  syphilis,  glanders,  and  small-pox)  are  comparatively  harmless 
when  swallowed,  though  most  deadly  when  introduced  directly 
into  the  blood,  as  through  a  bite  or  wound.  A  full  stomach 
may  delay  the  absorption  of  a  poison,  and  consequently  the 
toxic  symptoms,  for  several  hours.  The  circulating  poison  is 
gradually  eliminated  (As  in  fifteen  to  thirty  days),  a  part  hav- 
ing been  stored  up  in  the  tissues  for  a  variable  period.  It  is 
believed  that  toxic  effects  are  due  entirely  to  that  portion  of 
the  poison  present  in  the  capillaries.  Gaseous  poisons  appear 
to  be  eliminated  almost  instantly  by  the  lungs,  no  matter  how 
introduced.  A  poison  may  gain  entrance  into  the  human  sys- 
tem through  the  body  of  an  animal  without  the  latter  being 
affected  by  it.  Thus,  cows  and  goats  feed  on  stramonium  with 
impunity,  yet  their  milk  becomes  poisonous  to  human  beings. 

How  shall  we  determine  that  a  person  has  been  poisoned, 
(336) 


ACUTE  POISONING.  337 

accidentally  or  feloniously?  Usually  by  th*e  sudden  advent  of 
suspicious  symptoms  shortly  after  taking  food  or  drink,  if  acci- 
dental or  homicidal;  if  suicidal,  traces  of  the  poison  itself,  and 
not  infrequently  the  container,  are  to  be  found.  In  most 
cases  the  individual  affected  has  been  in  previous  good  health. 
Symptoms  of  poisoning  may  be  masked  by  alcoholism  or  sick- 
ness. 

The  most  common  symptoms  of  acute  poisoning  are  vio- 
lent pain,  vomiting,  purging,  convulsions,  delirium,  and  drowsi- 
ness: one  or  a  few  or  all  of  these.  It  must  not  be  forgotten, 
however,  that  toxic  symptoms  are  simulated  by  many  diseased 
conditions.  Thus,  cholera,  cholera  morbus,  perforative  peri- 
tonitis, ileus,  and  hernia  resemble  acute  As  poisoning  as  to  the 
pain,  vomiting,  and  purging;  strychnin  poisoning^closely  simu- 
lates tetanus;  and  coma  is  the  foremost  symptom  in  apoplexy, 
alcoholism,  and  insolation,  as  well  as  in  opium  poisoning.  Even 
the  post-mortem  appearances  of  disease  may  resemble  those 
found  after  death  from  poisoning,  and  the  poison  may  indeed 
have  been  introduced  into  the  body  after  death,  as  by  embalm- 
ing processes  or  by  injection  into  the  stomach  or  the  rectum. 
In  the  latter  event  some  of  the  poison  will  pass  by  osmosis 
into  the  liver  and  other  adjacent  viscera.  Suffocation  by  in- 
halation of  vomited  matters  is  often  the  direct  cause  of  death 
in  alcoholism  and  CO  poisoning. 

Circumstantial  evidence,  such  as  finding  poison  in  the  food 
or  drink,  is  of  great  importance,  but  is  not  absolutely  conclu- 
sive. The  ordinary  chemic  tests  are  generally  sufficient  for 
revealing  the  presence  of  a  poison  in  a  body,  but  one  must  bear 
in  mind  how  closely  certain  ptomains  resemble  in  reaction 
the  vegetable  alkaloids.  To  separate  inorganic  substances  for 
chemic  analysis  boil  the  finely  minced  stomach  or  other  matters 
with  HC1  and  crystals  of  KC103  until  a  straw-colored  liquid 
results;  treat  this  with  NaHS03  till  a  distinct  odor  of  S02  is 
noted;  then  pass  H2S  through  the  concentrated  liquid,  throw- 
ing down  most  metals  as  sulphids,  from  which  a  bead  is  readily 
obtained  by  reduction.  Such  destructive  methods  cannot  be 
used  for  isolating  organic  compounds.  Dialysis  is  a  ready 
means  of  separating  crystalloid  poisons  from  the  colloids  in 
the  stomach  or  intestines.  Microchemic  methods  are  of  special 
service  in  medico-legal  cases.  In  case  of  doubt  physiologic  tests 
should  be  made  upon  living  animals,  with  control  tests  with 
equivalent  amounts  of  the  substance  suspected  to  be  present. 
Distillation  is  indicated  in  the  separation  of  HCN"  and  other 
volatile  compounds.  Alkaloids  are  isolated  by  acidulating  the 
suspected  material,  heating  carefully  over  the  water-bath,  filter- 


338  TOXICOLOGY. 

ing,  washing  with -boiling  distilled  water,  evaporating  the  fil- 
trate, rubbing  up  residue  with  distilled  water,  and  again  filter- 
ing until  a  fairly  pure  product  is  obtained;  then  neutralizing 
with  NaHC03,  taking  up  freed  alkaloid  with  ether  or  chloro- 
form and  evaporating  spontaneously,  leaving  the  pure  alkaloid 
ready  for  testing. 

Stas's  method  for  separating  morphin  and  strychnin  from 
other  substances  is  to  render  the  vomit  alkaline  with  Na2C03 
and  shake  liquid  with  four  volumes  of  ether  or  amylic  alcohol 
(best  for  morphin);  let  fluids  separate,  remove  ethereal  or  alco- 
holic solution,  and  allow  to  evaporate. 

The  local  effects  of  poisons  include  erosion  of  mucous 
membrane  (mineral  acids  and  caustic  alkalies),  irritation  or 
inflammation  (irritant  poisons  generally),  and  special  sensa- 
tions, such  as  the  tingling  of  the  tongue  produced  by  aconite, 
the  dry  throat  of  belladonna,  and  the  local  anesthesia  of  cocain. 
The  mouth  is  bleached  in  poisoning  by  carbolic  acid,  HgCl2, 
AgN"03,  potash,  or  soda  (mucosa  swollen,  translucent,  brown, 
and  soapy).  The  odor  of  the  drug  on  the  breath  is  perceptible 
in  poisoning  by  HCN,  laudanum,  alcohol,  phenol,  creasote, 
chloroform,  I,  P,  camphor,  nitrobenzol,  NH3,  and  acetic  acid. 
Certain  poisons  have  an  elective  affinity  for  various  organs, 
as  strychnin  for  the  spinal  cord,  prussic  acid  for  the  heart,  and 
opium  for  the  brain. 

The  remote  effects  of  poisons  are  either  common,  as  fever, 
or  specific.  Thus,  the  pupils  are  dilated  by  belladonna,  atropin, 
hyoscyamus,  stramonium,  aconite,  alcohol,  chloroform,  conium, 
and  opium  (last  stage).  They  are  contracted  by  opiates,  eserin, 
phenol,  or  chloral  (during  sleep).  Coma  is  noted  with  opiates, 
alcohol,  chloral,  chloroform,  carbolic  acid,  and  camphor.  The 
chief  deliriants  are  the  nightshade  family,  cannabis  Indica,  alco- 
hol, and  camphor.  Convulsions  are  common  symptoms  with 
nearly  every  kind  of  poison,  being  probably  due  to  reflex  action, 
in  the  same  way  as  teething  or  worms  may  excite  them.  Te- 
tanic spasms  are  observed  with  nux  vomica  or  strychnin,  and 
less  often  from  brucin,  Sb,  As,  or  even  intense  pain.  Paralysis 
may  occur  in  poisoning  by  eserin,  conium  (from  below  upward), 
aconite,  and  in  chronic  metallic  poisoning.  The  mouth  and 
tongue  are  dry  in  belladonna,  hyoscyamus,  stramonium,  and 
opium  poisoning.  Salivation  may  be  due  to  Hg,  As,  NH3,  pilo- 
carpin,  muscarin,  cantharis,  and  corrosives  generally.  The  skin 
is  dry  in  poisoning  by  any  of  the  nightshade  family.  It  is  moist 
in  poisoning  by  opium  and  depressants  generally  (aconite,  alco- 
hol, tobacco,  lobelia,  Sb,  etc.).  A  scarlet  rash  is  noted  in  bella- 
donna or  stramonium  poisoning  and  in  ptomain  poisoning  from 


ACUTE  POISONING.  339 

decayed  meat  or  fish;  urticaria  in  opium,  chloral,  cubebs,  and 
salicylic  acid;  eczema  from  As;  acne  from  tar  or  KBr;  pustular 
eruptions  from  Sb  or  croton-oil;  petechias  from  KI. 

The  blood  is  turned  carmin  by  CO  and  KCN;  dark  by 
HCN;  brick-red  (in  contact)  by  carbolic  acid;  black  in  contact 
with  HN03;  chocolate-brown,  with  destruction  of  red  cells,  by 
KC103  and  other  reducing  agents;  dark  and  free  from  clots  in 
alcohol  and  narcotic  poisoning  and  all  conditions  causing  death 
by  asphyxia  (nitrobenzol,  strychnin,  belladonna,  most  glucosids, 
KC103,  K2Cr207)  or  syncope  (aconite,  digitalis). 

The  medico-legal  duties  of  the  practitioner  in  cases  of  sup- 
posed poisoning  are:  first,  to  preserve  the  life  of  the  patient 
if  possible;  and,  second,  to  forward  justice  by  writing  down  his 
observations  on  the  case  as  quickly  as  practicable.  He  should 
also  take  charge  of  any  suspected  food,  medicine,  vomit,  urine, 
or  feces,  and  seal  them  in  new,  clean  vessels  duly  labeled  for 
examination. 

In  the  post-mortem  examination  (preferably  within  twenty- 
four  hours)  a  double  ligature  should  be  passed  around  the 
esophagus  in  the  chest,  and  another  around  the  duodenum  a 
few  inches  below  the  pylorus.  The  stomach  is  removed  intact 
by  cutting  between  each  pair  of  ligatures,  and  is  opened  along 
the  lesser  curvature  as  soon  as  possible  and  its  lining  spread  out 
and  examined  with  a  hand-lens  for  particles  of  poison.  Another 
ligature  should  be  tied  low  down  in  the  rectum  and  the  intestine 
removed  to  a  separate  clean  vessel  and  scrutinized  carefully. 
As  much  blood  as  possible  should  be  secured  for  the  chemist; 
also  a  part  or  the  whole  of  the  liver,  brain,  spinal  cord,  kidney, 
spleen,  and  thoracic  viscera,  and  a  large  piece  of  muscle  from 
the  thigh  or  a  portion  of  bone.  In  corrosive  poisoning  the 
mouth,  esophagus,  stomach,  and  duodenum  should  be  removed 
together.  Poisons  are  found  in  their  greatest  purity  in  the 
kidneys  and  urine.  The  normal  vivid  congestion  of  the  stomach 
after  meals  and  the  common  post-mortem  suffusions  and  auto- 
digestion  of  the  stomach  ought  not  to  be  mistaken  for  toxic 
lesions.  Perforation  due  to  a  corrosive  differs  from  the  small 
aperture  of  disease  in  being  large  and  ragged,  with  soft,  friable 
edges. 

The  post-mortem  examination  should  be  as  thorough  as 
possible  in  order  to  discover  if  the  sudden  and  fatal  end  were 
not  due  to  some  latent  disease;  for  instance,  to  the  perforation 
of  an  unrecognized  gastric  or  typhoid  ulcer.  The  mouth,  lips, 
and  tongue  should  be  carefully  examined  for  stains  or  erosions, 
and  the  skin  for  hypodermic  punctures. 

Decomposition  of  organs  is  best  prevented  by  freezing,  but 


340  TOXICOLOGY. 

pure  alcohol  may  be  utilized  if  necessary.  The  presence  of  As 
in  appreciable  quantities  retards  putrefaction  for  long  periods. 
The  jars  should  be  sealed  by  attaching  tape  to  both  jar  and 
cover  by  means  of  sealing-wax,  the  seal  being  retained,  and  a 
signed  and  dated  label  should  be  placed  on  each  jar. 

For  practical  purposes  acute  poisons  may  be  divided  into 
three  main  classes:  corrosives,  irritants,  and  neurotics.  The 
first  two  affect  principally  the  alimentary  tract;  the  last,  the 
nervous  system.  Corrosive  poisons  differ  from  irritants  mainly 
in  the  intensity  and  rapidity  of  the  symptoms,  and  a  drug  may 
be  either  irritant  or  corrosive  according  to  the  amount  ingested 
or  the  degree  of  dilution.  The  cause  of  death  from  irritants 
is  gastro-enteritis,  with  or  without  specific  remote  effects.  Cor- 
rosives cause  death  by  acute  laryngitis  with  edema,  perforation 
of  stomach,  gastro-enteritis,  shock,  or  slow  starvation. 

Neurotic  poisons  have  been  subdivided  into  a  number  of 
varieties  corresponding  with  the  leading  or  selective  action  of 
the  various  drugs.  Narcotics  (opium,  for  example)  act  chiefly 
upon  the  brain,  causing  stupor  and  finally  death  from  paralysis 
of  the  vital  nerve-centers.  Anesthetics  produce  fatal  effects 
in  the  same  manner,  or  indirectly  by  mechanic  interference 
with  respiration,  as  when  a  patient  chokes  to  death  from  vom- 
iting of  bronchial  mucus.  The  third  stage  of  alcoholic  inebria- 
tion, like  that  of  anesthesia,  is  simply  a  narcosis,  and  should 
be  treated  in  the  same  manner  as  the  latter.  The  solanaceous 
deliriants  act  chiefly  on  the  brain,  producing  delirium.  Some 
neurotics  (strychnin,  for  example)  cause  death  by  tetanic  fixa- 
tion of  the  muscles  of  respiration.  The  opposite  condition  of 
motor  paralysis  is  noted  with  conium,  curare,  and  Calabar  bean. 
Others,  like  aconite  and  prussic  acid,  lead  to  death  by  syncope: 
that  is,  cardiac  paralysis.  A  lethal  result  may  follow  over- 
stimulation  of  the  heart,  leading  to  exhaustion,  as  in  the  case 
of  digitalis. 

Most  irritant  poisons  belong  to  the  mineral  kingdom, 
whereas  nearly  all  neurotics  are  of  vegetable  origin.  Animal 
poisons  taken  by  the  mouth  usually  act  as  irritants;  when  re- 
ceived directly  into  the  blood,  as  in  dissection  wounds,  they  play 
the  part  of  depressing  neurotics.  Poisonous  gases  owe  their 
injurious  effects  either  to  an  irritant  congesting  action,  as  Cl 
and  Br;  to  chemic  decomposition  of  the  blood,  as  CO  and  H2S; 
or  to  a  depressing  influence  upon  the  respiratory  center,  as  C02. 

The  treatment  of  ordinary  irritant  poisoning  consists,  in 
general,  of  the  following  steps:  1.  The  administration  of  the 
chemic  antidote,  which  means  any  safe  and  proper  substance 
that  will  form,  with  the  poison,  an  insoluble  or  innocuous  com- 


ACUTE  POISONING.  341 

pound.  2.  The  production  or  encouragement  of  emesis,  or 
emptying  the  stomach  with  the  siphon  rubber  tube  or  pump. 
If  the  tube  is  employed,  the  stomach  may  be  washed  out  with 
a  solution  of  the  antidote  or  with  diluted  milk  or  some  other 
soothing  liquid.  The  best  systemic  emetic  is  apomorphin 
hydrochlorate,  of  which  yi5  to  1/10  grain  (for  an  adult)  may 
be  injected  hypodermically,  and  be  repeated,  if  necessary, 
within  twenty  or  thirty  minutes;  this  drug  will  evidently  be  of 
no  avail  in  deep  narcosis,  in  which  condition  we  use  preferably 
the  tube  or  pump.  In  the  absence  of  the  above-mentioned 
means  of  emesis,  we  may  employ  tepid  or  greasy  water  in 
quantity,  or  a  dessertspoonful  of  ground  mustard  or  common 
salt  in  a  glass  of  warm  water,  or  ZnS04,  20  to  30  grains  (5 
grains  for  children)  in  water,  or  for  children  a  teaspoonful  of 
syrup  of  ipecac;  the  simple  operation  of  tickling  the  fauces  is 
likewise  not  to  be  despised  as  a  means  to  the  end.  3.  The 
administration  of  demulcent  drinks  to  allay  irritation  and  pre- 
vent., to  some  extent,  the  further  injurious  action  of  the  poison. 
Mucilaginous  (linseed,  acacia,  barley,  starch  paste,  oatmeal- 
gruel)  and  albuminous  (eggs  and  milk)  preparations  serve  a 
useful  purpose  here.  4.  Emptying  the  bowels  of  any  poison 
that  may  be  retained  there,  as  well  as  of  the  antidotal  com- 
pounds, which  would  gradually  undergo  solution  and  absorp- 
tion. Castor-oil  (a  tablespoonful)  and  Epsom  salts  (1  to  4 
ounces)  are  most  generally  useful.  Croton-oil,  1  to  5  minims 
on  a  bread  pill,  is  quite  efficient.  Senna,  gamboge,  and  other 
drastics  are  best  in  narcotic  poisoning.  5.  Allaying  pain  by 
hot  external  applications  and  morphin  hypodermically.  6. 
Combating  shock  with  the  stimulants  at  hand  and  doing  what- 
ever else  judgment  and  common-sense  would  dictate. 

In  the  treatment  of  corrosive  poisoning  we  use  preferably, 
if  anything,  the  soft-rubber  tube  for  emptying  the  stomach,  on 
account  of  the  danger  of  rupture  of  the  weakened  walls.  Neu- 
rotic poisons  require,  in  addition  to  antidotes  and  evacuation, 
the  administration  of  their  respective  physiologic  antagonists, 
as  chloral  and  chloroform  against  strychnin;  atropin  and  caffein 
against  morphin;  brandy  against  aconite,  etc.  It  is  well  to 
be  careful  in  this  connection  so  as  not  to  substitute  one  kind 
of  neurotic  poisoning  for  another,  and,  generally  speaking,  not 
more  than  the  physiologic  dose  of  the  opposing  drug  should  be 
exhibited. 

In  the  treatment  of  acute  poisoning  time  is  a  very  impor- 
tant factor,  and  the  measures  employed  should  be  as  rapid  and 
energetic  as  possible.  It  will  frequently  occur  that  some  of  the 
more  eligible  antidotes  are  not  at  hand,  nor  to  be  had  in  a 


342  TOXICOLOGY. 

very  short  time.  While  waiting  for  their  arrival  it  is  well  to 
use  at  once  such  other  remedial  methods  as  knowledge  and 
judgment  will  dictate.  Like  other  derangements  of  the  bodily 
functions,  every  case  of  poisoning  must  be  treated  on  its  pecul- 
iar indications,  and  no  amount  of  information  can  take  the 
place  of  intelligent  presence  of  mind. 

• 

ANTIDOTES  IN  GENERAL. 

Magnesia,  1  part  to  25  of  warm  water  (1 1/2  to  2  ounces 
at  short  intervals),  is  the  most  efficient  antidote  against  acids 
and  acid  salts,  and  is  also  valuable  in  poisoning  by  metallic 
salts,  such  as  arsenic.  Calcium  hydrate  and  carbonate  (lime- 
water,  chalk,  egg-  or  oyster-  shells)  are  also  good  antidotes  for 
acids,  especially  oxalic,  and  oxalates.  The  carbonates  and  bicar- 
bonates  of  Na  and  K  may  be  used  against  most  poisonous 
metallic  salts,  particularly  those  of  zinc.  They  are  also  useful 
against  K2Cr207,  forming  the  neutral  chromate.  Ferric  hy- 
droxid  is  the  antidote  par  excellence  (10  to  1)  for  arsenic.  Soap- 
suds (1  to  4  of  water)  by  the  cupful  is  a  most  effective  antidote 
against  corrosive  acids  and  salts.  Copper  carbonate,  3  to  6 
grains  with  sugar  and  water,  preceded  and  followed  by  an 
emetic,  is  recommended  for  P  poisoning.  Dilute  H2S04  is  used 
as  an  antidote  for  soluble  salts  of  Pb  and  Ba.  Diluted  NH3 
by  inhalation  is  useful  against  vapors  of  corrosive  acids,  nitro- 
benzol,  Cl,  Br,  and  HCN.  Sodium  hyposulphite,  15  grains  in 
very  dilute  solution  frequently  repeated,  is  a  good  antidote  for 
bleaching  powder  and  other  hypochlorites. 

Gum  arabic  in  copious  draughts  is  recommended  against 
toxic  symptoms  from  Bi  salts.  Starch  paste  (1  to  15)  neutralizes 
I  and  Br.  Oils  and  fats  are  efficient  antidotes  for  caustic  alka- 
lies and  metallic  oxids.  They  should  be  avoided  in  poisoning 
by  P,  carbolic  acid,  cantharis,  or  Cu  salts.  Weak  vegetable  acids 
are  of  service  against  corrosive  alkalies.  Albumin  is  an  ideal 
antidote  for  most  metallic  salts,  and  is  effective  against  acids, 
alkalies,  I,  Br,  Cl,  creasote,  anilin,  and  alcoholic  solutions  of 
alkaloids.  It  should  be  given  well  diluted  (whites  of  4  eggs  to 
a  quart  of  tepid  water)  and  be  followed  by  emetics  and  cathar- 
tics: Milk  is  a  good  substitute  for  egg-albumin,  but  is  contra- 
indicated  if  fats  are. 

Tannic  acid  (15  to  45  grains  in  a  2-per-cent.  solution  every 
quarter-hour)  is  an  efficient  chemic  antidote  for  all  alkaloidal 
salts  and  for  tartar  emetic.  Its  effect  is  enhanced  by  the  addi- 
tion of  10  per  cent,  of  I.  As  a  household  remedy,  it  may  be 
given  in  the  form  of  a  strong  infusion  or  decoction  of  green  tea. 


CORROSIVES.  343 

K2Mn208,  grain  for  grain  of  the  poison  and  well  diluted,  is 
useful  as  an  oxidizing  agent  against  all  organic  compounds, 
when  the  poison  is  still  in  the  stomach.  Animal  charcoal  has 
also  been  used  as  an  antidote  for  alkaloids,  which  it  renders 
more  or  less  inert  by  absorbing  them.  Iron  filings  are  antidotal 
to  Cu  or  Hg  poisoning. 

If  the  nature  of  the  poison  is  quite  unknown,  a  harmless 
and  useful  antidote  is  made  with  equal  parts  of  magnesia,  wood- 
charcoal,  and  ferric  hydrate,  given  freely  in  plenty  of  water. 


CORROSIVES. 

The  general  symptoms  of  corrosive  poisoning  are  severe 
and  immediate  burning  pain  in  the  mouth,  throat,  stomach, 
and  abdomen  (increased  by  pressure);  staining  and  erosion  of 
the  mucous  membrane  of  the  mouth  and  throat;  vomiting  of 
stomach-contents,  mixed  with  mucus  and  blood,  and  often  fol- 
lowed by  bloody  purging  (constipation  with  mineral  acids); 
dysphagia,  dyspnea,  aphonia;  headache  and  marked  prostration 
— pulse  small  and  weak,  skin  cool  and  sweating;  convulsions 
common;  painful  cramps  in  calves;  urine  scanty  or  suppressed; 
mind  usually  clear;  peculiar  drawn,  haggard  facies.  Common 
sequels  in  case  of  recovery  are  nephritis  and  esophageal 
stricture. 

MINERAL  ACIDS. 

These  include  nitric,  hydrochloric,  sulphuric,  phosphoric, 
and  chromic.  All  produce  acid  vomit  and  dry  eschars.  The 
tissues  are  stained  yellow  by  nitric;  white  or  grayish,  turning 
brownish,  by  hydrochloric;  light  yellow,  becoming  gray-brown, 
by  chromic;  dark  gray-brown  and  deep  eschars  by  sulphuric 
acid.  The  vomit  is  brown  with  nitric  acid;  dark  yellow  with 
hydrochloric;  dark  with  sulphuric;  and  yellow-red  or  green 
with  chromic.  Black  woolen  cloth  is  stained  yellow  by  nitric 
acid  (quickly  burns  a  hole);  bright  red  or  green  by  hydro- 
chloric; wet  red  by  sulphuric. 

The  smallest  fatal  dose  of  mineral  acids  ranges  from  1 
dram  H2S04  to  4  drams  HC1;  less  than  1/2  grain  of  Cr03  has 
proved  fatal.  The  usual  period  of  death  is  from  eighteen  to 
twenty-four  hours,  though  much  sooner  if  the  acid  acts  directly 
on  the  respiratory  apparatus.  The  best  antidotes  for  the  min- 
eral acids  are  mild  alkaline  drinks  ad  libitum,  such  as  lime- 
water,  soap-suds,  and  heavy  magnesia  suspended  in  milk.  If 
these  are  not  at  hand,  give  lime  from  the  walls,  chalk,  or 


344  TOXICOLOGY. 

baking-soda.  Dilute  the  acid  with  plenty  of  water.  Small 
pieces  of  ice  may  be  given  for  too  severe  retching.  Coma  may 
be  opposed  by  subdermic  injections  of  ]Sra2C03.  For  external 
vitriol  burns  soda  is  a  good  antidote  after  wiping  off  the  acid 
with  a  dry  cloth. 

VEGETABLE  ACIDS. 

These  also  produce  acid  vomit  and  dry,  white  eschars. 
Oxalic  acid  is  characterized  by  a  very  sour  taste;  it  may  pro- 
duce coma  or  tetanic  convulsions.  It  causes  an  orange  stain 
on  black  cloth.  A  dram  has  produced  death  within  an  hour. 
Acetic  acid  is  distinguished  by  the  odor  of  vinegar.  Tartaric 
acid  yields  a  burnt-sugar  odor  on  heating.  Lime-water  is  a 
good  antidote  for  all  three  vegetable  acids,  particularly  for 
oxalic.  Other  antidotes  are  magnesia,  soap-suds,  chalk,  baking- 
soda,  wall-plaster,  whiting,  and  tooth-powders. 

CAUSTIC  ALKALIES. 

This  class  includes  alkaline  hydrates  and  oxids  and  car- 
bonates (lye,  washing-soda,  sal  volatile).  They  produce  brown- 
ish, ropy,  alkaline,  mucous,  bloody,  soapy,  frothy  vomit  and 
wet,  sloughing  sores.  They  have  a  very  acrid,  burning  taste. 
CEdema  glottidis  is  very  liable  to  be  caused  by  ammonia. 
Strong  hydrates  leave  a  brown  stain  on  black  cloth.  The  small- 
est fatal  dose  on  record  is  40  grains  of  potassa. 

Death  usually  takes  place  within  a  few  hours.  Caustic 
alkalies  are  safely  and  readily  neutralized  by  an  abundance  of 
any  fixed  oil  (linseed,  almond,  olive,  cotton-seed)  or  fat  (butter, 
lard),  forming  thereby  a  soap.  Weak  vegetable  acids,  such  as 
lemon-juice  or  orange-juice  and  vinegar,  fulfill  similar  indica- 
tions, but  less  acceptably.  Demulcent  drinks  should  be  given 
freely.  Emetics  and  the  stomach-pump  are  contra-indicated. 

CHLORIDS. 

Corrosive  sublimate  may  produce  toxic  symptoms  as  bed- 
bug poison,  antiseptic  tablets,  or  vaginal  douches.  It  has  a 
styptic,  metallic  taste,  and  coats  the  lips  and  tongue  white. 
The  vomit  is  glairy  or  bloody.  Cramps  of  the  extremities  are 
common.  It  corrodes  and  darkens  metals.  The  smallest  fatal 
dose  on  record  is  3  grains;  time,  one-half  to  five  days.  White 
of  egg  is  the  best  antidote,  1  for  every  4  grains.  The  resulting 
albuminate  should  be  removed  quickly  to  prevent  its  solution 
in  the  digestive  juices.  Death  is  due  to  collapse,  coma,  or  con- 
vulsions. 


IRRITANTS.  345 

The  butter  of  antimony  causes  grumous  vomit,  violent 
purging,  and  great  depression.  The  chlorid  of  zinc,  used  in 
soldering  and  embalming  fluids,  has  killed  in  the  dose  of  6 
grains.  Baking-soda  in  plenty  of  water,  as  well  as  eggs  or  milk, 
is  indicated. 

NITRATES. 

Saltpeter  causes  frequent  urination,  tremors,  convulsions, 
delirium,  prostration,  or  collapse.  An  ounce  of  it  has  caused 
death  in  about  two  hours. 

Lunar  caustic  shows  a  glazed  appearance  of  the  mucous 
membrane,  and  the  vomit  darkens  on  exposure  to  light.  Fifty 
grains  has  caused  death.  Common  salt  is  the  antidote. 

PHENOLS. 

Carbolic  acid  produces  hard,  white  patches  in  the  mouth, 
frothy  vomit,  contracted  pupils,  blackish-green  urine,  speedy 
coma,  and  collapse.  The  breathing  is  slow  and  deep  at  first; 
shallow  and  hurried  toward  the  end.  The  breath  has  the  pecul- 
iar odor  of  the  acid,  which  gives  a  violet  color  with  Fe2Cl6.  A 
half-dram  has  proved  fatal;  the  period  of  death  ranges  from 
one-half  to  twelve  hours.  Alcoholics  serve  as  the  choice  of 
antidotes,  and  further  as  needed  stimulants.  Epsom  or  Glauber 
salts  are  also  useful  remedies.  The  stomach  should  be  cleared 
out  quickly  with  the  tube  or  apomorphin.  Oils  and  fats  must 
be  avoided. 

Other  phenols  which  may  produce  poisonous  effects  are 
cresols,  creasote,  guaiacol,  salol,  and  creolin. 


IRRITANTS. 

The  symptoms  of  irritant  poisoning  are  similar  to  those  of 
corrosives,  but  are  generally  less  intense,  and  do  not  come  on 
for  some  minutes  or  hours.  Great  thirst,  severe  headache, 
giddiness,  cramps  in  the  legs,  torpor,  coma,  and  convulsions  are 
common  symptoms.  Dilute  mineral  acids  and  other  corrosives 
may  act  as  irritant  poisons. 

MINERAL. 

Arsenic  is  present  in  white  arsenic,  fly-paper,  fly-powder, 
"Hough  on  Rats,"  Scheele's  green  (candy,  wall-paper),  Paris 
green,  cancer  cures,  colored  crayons,  and  artificial  flowers. 
Special  symptoms  of  arsenical  poisoning  are  the  suffused  and 
reddened  eyes,  brown  vomit  often  mixed  with  bloody  mucus, 


346  TOXICOLOGY. 

bloody  or  choleraic  stools  with  tenesmus,  subnormal  tempera- 
ture, and  prominent  nervous  symptoms.  The  skin  is  cold  and 
clammy.  The  urine  is  often  partly  suppressed.  Pain  is  gen- 
erally severe,  but  may  be  slight  or  'absent;  numbness  and 
tingling  are  complained  of.  The  symptoms  usually  begin  in 
from  fifteen  to  sixty  minutes.  The  smallest  fatal  dose  was  1 1/2 
grains;  fatal  period,  two  to  twenty-four  hours;  average,  ten. 
A  simple  test  for  As  is  the  garlicky  odor  noticed  on  heating 
the  powder,  or  the  lemon-yellow  ppt.  with  H2S. 

After  thoroughly  emptying  the  stomach  with  the  pump, 
tube,  or  emetic,  one  should  neutralize  the  remaining  poison 
that  cannot  be  washed  away.  This  is  done  by  means  of  mag- 
nesia with  freshly  made  magma  of  ferric  hydrate  (made  by 
mixing  equal  parts  of  tincture  of  iron  and  ammonia-water,  and 
straining  and  washing  the  precipitate),  of  which  the  dose  is  a 
tablespoonful  every  half-hour  for  four  to  six  doses.  This  forms 
insoluble  Fe3(As04)2. 

Demonstration  of  Antidote  for  Arsenical  Poisoning.  —  Render 
Fe2Cl6  solution  alkaline  with  NH4OH,  throwing  down  ppt.  of  Fe2(HO)« 
on  a  cloth;  wash  clear  of  NH3,  and  then  stir  the  ppt.  into  a  beaker  con- 
taining an  arsenic  solution.  After  five  minutes  filter  and  prove  absence 
of  As  in  filtrate. 

Another  good  antidote  for  arsenic  is  dialyzed  iron.  Stimu- 
lants (brandy,  aromatic  spirit  of  ammonia,  strychnin)  should  be 
given  hypodermically  for  faintness,  and,  if  the  patient  is  cold, 
use  hot  blankets.  After  the  sickness  subsides  an  ounce  or  two 
of  castor-oil  should  be  given. 

Antimony  poisoning  is  characterized  especially  by  excessive 
vomiting  and  depression;  also  by  a  strong  metallic  taste,  by 
early  salivation,  profuse  sweats,  and  rice-water  stools.  The 
urine  is  usually  increased,  with  painful  micturition.  Two 
grains  of  tartar  emetic  have  caused  death.  Tannin  is  the  best 
antidote;  ferric  hydrate  is  next  best.  Encourage  vomiting  with 
warm  drinks,  stimulate  freely,  and  keep  patient  warm  with  hot 
blankets  and  bottles. 

Acute  lead  poisoning  is  manifested  by  intense  abdominal 
pain,  with  hard,  retracted  abdomen  and  constipation;  the  stools 
are  black.  If  the  case  is  protracted,  local  paralyses  and  the 
blue  line  on  the  gums  appear.  Any  lead  salt  or  solution  turns 
black  with  H2S;  lead  salts  are  also  easily  reduced  to  a  bead. 
One  ounce  of  sugar  of  lead  has  proved  fatal.  Any  sulphate 
(preferably  MgSOJ  will  ppt.  Pb  solutions  and  act  as  an  anti- 
dote. A  hypodermic  of  morphin  will  usually  be  required  for 
the  pain. 


IRRITANTS.  347 

Copper  poisoning  (blue  vitriol,  verdigris)  excites  greenish 
vomit  and  a  very  marked  metallic  taste.  In  acid  solution  me- 
tallic copper  is  pptd.  on  a  knife-blade.  Milk  and  eggs  are 
antidotes. 

The  chlorid  of  tin  used  in  dyeing  has  sometimes  given  rise 
to  toxic  effects.  It  is  more  depressant  than  irritating.  A  frag- 
ment of  Zn  ppts.  the  metal  in  arborescent  form.  Milk  and  eggs 
are  in  order;  magnesia  is  also  an  antidote. 

Both  copperas  and  tincture  of  iron  have  caused  death 
when  taken  in  very  large  doses  (1  Y2  ounces  of  tincture).  Iron 
solutions  turn  black  with  tannin  or  tea,  and  cause  a  dark- 
greenish  fur  on  the  tongue.  Baking-soda  or  magnesia  and  milk 
and  mucilaginous  drinks  are  indicated. 

Common  alum  in  very  large  doses  may  produce  toxic 
symptoms.  It  has  a  sweetish,  styptic  taste,  and  there  is  some- 
times frothing  at  the  mouth.  The  chief  antidotes  are  milk  and 
baking-soda. 

Zinc  sulphate  in  large  doses  causes  excessive  vomiting, 
dilated  pupils,  and  coma.  One-half  ounce  has  proved  fatal  in 
about  twelve  hours.  Vomiting  should  be  encouraged  by  copious 
draughts  of  warm  water.  Antidotes  are  lime-water,  albumin, 
soap-suds,  and  tannin. 

Potassium  dichromate  has  caused  death  in  a  number  of 
instances,  2  drams  being  the  smallest  fatal  dose.  The  vomit 
is  yellow,  the  pupils  dilated,  and  there  is  violent  purging.  Am- 
monia-water gives  a  green  ppt.  Lime-water  or  magnesia  and 
milk  are  good  antidotes. 

Barium  salts  cause  nervous  symptoms,  cardiac  palpitation, 
disturbed  vision,  and  great  weakness.  One  dram  has  proved 
fatal.  Epsom  or  Glauber  salts  are  purgative  antidotes,  and 
should  be  followed  by  emetics  and  by  fixed  oils  to  soothe.  The 
flame  test  is  greenish. 

The  chlorate,  sulphate,  and  bitartrate  of  potassium  are  all 
capable  of  exciting  toxic  symptoms;  4  drams  of  chlorate  have 
caused  death,  and  1  1/2  ounces  of  cream  of  tartar  likewise.  The 
chlorate  is  marked  by  rigid  limbs,  delirium,  coma,  and  bloody 
urine.  The  bitartrate  poisoning  resembles  that  by  niter.  So- 
dium bicarbonate  neutralizes  the  bitartrate.  Opium,  stimu- 
lants, and  demulcents  are  called  for. 

Bleaching  powder  taken  internally  acts  as  an  irritant 
poison.  It  has  a  sharp,  acid  taste  and  a  distinct  odor  of  chlorin. 
It  is  best  counteracted  by  lime-water  and  oils. 

lodin  solutions  in  large  doses  are  marked  by  an  acrid  taste, 
tightness  about  the  throat,  pain,  vomiting,  and  purging;  yellow 
stains  are  noted  on  the  mucous  membrane.  Starch  or  flour  in 


348  TOXICOLOGY. 

warm  water  should  be  given  till  the  blue  color  disappears  from 
the  vomit.    White  of  eggs  and  milk  should  follow. 

Phosphorus  .poisoning  may  occur  from  swallowing  match- 
heads,  ratsbane,  or  phosphorated  oil,  or  by  inhalation  of  phos- 
phine.  Special  symptoms  are  a  garlicky  odor  and  taste;  grad- 
ually increasing  pain,  beginning  over  the  region  of  the  liver 
within  an  hour  to  several  days;  jaundice  on  second  or  third 
day;  muscular  twitchings;  albuminuria,  hematuria,  or  sup- 
pressed urine  (contains  leucin  and  tyrosin);  paralysis,  coma, 
and  collapse.  The  vomit  is  greenish  or  coffee-ground  in  color, 
and  both  it  and  the  stools  are  luminous  in  the  dark,  especially 
on  heating  with  sulphuric  acid.  One-fiftieth  grain  has  caused 
death  in  from  one  to  four  days.  There  is  no  direct  antidote 
for  phosphorus.  Useful  oxidizing  agents  are  potassium  per- 
manganate and  ozonized  turpentine  ("French  oil,"  1/2  dram 
every  half-hour  for  five  or  six  doses).  As  an  emetic,  copper 
sulphate  is  commonly  used:  3  grains  well  diluted  every  fifteen 
minutes  till  vomiting  occurs.  Albuminous  and  mucilaginous 
drinks  and  milk  or  magnesia  should  be  given,  but  no  oils  or 
fats.  Oxygen  inhalations  are  recommended.  Post-mortem  ex- 
amination shows  fatty  degeneration  of  the  liver,  kidneys,  heart, 
and  other  muscles. 

Demonstration  of  Antidote. — Place  a  bit  of  P  in  CuSO4  solution  for 
a  few  minutes,  and  note,  on  removal,  the  coating  of  Cu  on  the  piece  of  P. 

VEGETABLE. 

Many  resins  (aloes,  jalap,  gamboge,  scammony,  bryony, 
elaterium)  in  too  large  doses  cause  excessive  mucous  purging, 
with  intense  griping  pain  and  considerable  depression.  The 
stomach  should  be  emptied  and  castor-oil  given.  Morphin 
hypodermically,  mucilaginous  drinks,  emollient  enemata,  and 
hot  fomentations  are  also  useful.  It  is  important  to  counteract 
great  exhaustion. 

Certain  oils  (savin,  croton,  castor,  turpentine)  may  excite 
choleraic  vomiting  and  purging,  with  contracted  pupils,  ster- 
torous breathing,  strangury,  and  collapse.  Fifteen  minims  of 
croton-oil  have  proved  fatal.  The  white  of  eggs  is  the  chief 
antidote.  Epsom  salts  are  useful  against  turpentine,  for  which 
hot  fomentations  to  the  loins  are  also  serviceable.  Brandy, 
aromatic  ammonia,  or  other  stimulant  may  be  needed. 

Colchicum  preparations  sometimes  produce  violent  purg- 
ing, with  dilated  pupils,  cold  skin,  dyspnea,  and  rapid  exhaus- 
tion. Tannin  or  strong  tea  or  coffee  ppts.  the  active  principle, 
and  stimulants  are  necessary. 


IRRITANTS.  349 

Black,  green,  and  white  hellebore  or  veratrum  has  a  very 
acrid  and  bitter  taste,  and  causes,  in  poisonous  doses,  violent 
vomiting,  purging,  and  abdominal  pain,  with  marked  depres- 
sion. It  is  treated  like  colchicum  poisoning.  Ergot,  or  the 
fungus  of  rye,  often  taken  to  produce  abortion,  causes  dizziness, 
headache,  mydriasis,  dyspnea,  delirium,  coma,  and  heart-failure. 
It  has  a  peculiar,  nutty  odor.  Tannic  acid  is  the  antidote. 
Xitroglycerin  is  of  service,  and  small  doses  of  opium  may  be 
given  after  the  stomach  and  bowels  are  emptied.  The  patient 
should  be  kept  warm  in  the  recumbent  posture. 

The  symptoms  of  digitalis  poisoning  are  chiefly  a  feeble, 
slow,  intermittent  pulse;  nausea,  grass-green  vomiting,  and 
purging;  abdominal  pain,  vertigo,  pale  .face,  dilated  pupils; 
severe  headache,  delirium,  syncope;  cold,  clammy  skin;  chro- 
mopsia,  cyanosis,  convulsions,  paralysis,  coma.  Death  occurs 
from  sudden  heart-failure.  Poisoning  usually  takes  place 
from  the  cumulative  effect  of  the  drug  given  in  repeated  doses, 
rather  than  from  a  single  large  dose.  The  main  point  in  treat- 
ment is  to  keep  the  patient  in  a  horizontal  posture.  Brandy  is 
useful,  and  aconite  may  be  tried  in  very  small  doses  and  re- 
peated if  beneficial.  Tannin  or  strong  tea  should  be  given  to 
antidote  the  glucosids. 

Lathyrus,  or  vetches,  are  marked  by  an  initial  chill,  pain 
in  the  loins  and  legs,  a  girdle  sensation,  paresthesia,  lameness, 
and  gangrene. 

All  parts  of  the  yew-  and  laburnum-  trees  may  cause  toxic 
symptoms,  such  as  vomiting,  abdominal  pain,  narcosis,  con- 
vulsive movements,  and  dilated  pupils.  They  have  a  sweet 
taste.  Cytisin  warmed  with  nitric  acid  gives  an  orange-yellow 
color. 

ANIMAL. 

Cantharis,  or  Spanish  fly,  used  either  internally  or  exter- 
nally, may  cause  a  dull  pain  in  the  loins,  vesic  tenesmus,  stran- 
gury, priapism,  salivation,  and  bloody  vomit,  stools,  and  urine. 
It  blisters  skin  or  mucous  membrane.  One  should  look  for  the 
shining  gold-green  wing-cases  of  the  insects  with  a  hand-lens. 
One  ounce  of  the  tincture  has  resulted  fatally.  Give  plenty  of 
water  and  a  warm  bath;  empty  the  stomach  and  give  castor-oil. 
Charcoal,  linseed-tea,  mucilage,  milk,  morphin,  and  stimulants 
(by  the  rectum)  are  all  of  service. 

Botulismus  (sausage  or  meat  poisoning)  is  characterized  by 
dry  mouth,  vomiting,  purging,  constricted  throat,  vertigo,  di- 
lated pupils,  ptosis,  suffocation,  fever,  erythema,  thready  pulse, 
and  collapse.  The  putrid  section  of  meat  looks  dirty  grayish 


350  TOXICOLOGY. 

green,  soft,  and  smeary.  The  chief  indication  is  to  wash  out 
the  stomach  and  intestines  as  thoroughly  as  possible.  Mor- 
phin,  atropin,  and  strychnin  may  also  be  required. 

Galactotoxicons,  or  milk-poisons,  are  saprophytes  causing 
the  summer  diarrheas  of  infants,  with  vomiting,  prostration, 
and  stupor.  The  chief  indications  are  to  stop  the  milk,  give 
white  of  egg  and  water,  and  flush  the  stomach  and  bowels  fre- 
quently with  normal  saline  solution. 

Tyrotoxicon  (diazobenzene)  is  a  poison  sometimes  formed 
in  cheese,  ice-cream,  custard,  and  cream-puffs.  It  produces  dry- 
ness  and  constriction  of  the  throat,  purging,  vomiting,  weak 
pulse,  nervous  prostration,  and  delirium.  Thorough  washing 
of  the  stomach  and  intestines  should  be  performed,  and  hypo- 
dermic injections  of  strychnin,  brandy,  or  ammonia  will  prob- 
ably be  needed. 

Ichthyotoxins,  or  fish-poisons,  may  be  present  in  canned 
fish,  mussels,  or  "kakke."  The  symptoms  are  vomiting,  purg- 
ing, dyspnea,  fever,  scarlatinous  or  urticarial  rash,  often  dilated 
pupils,  painful  cramps  in  the  limbs,  marked  prostration,  con- 
vulsions, delirium,  and  insensibility.  The  treatment  is  the 
same  as  above. 

GASES. 

The  more  common  acid  vapors  are  bromin,  chlorin,  hydro- 
chloric acid,  and  nitrous  and  sulphurous  fumes.  They  excite 
coughing  and  suffocation,  conjunctival  and  pharyngeal  conges- 
tion, trembling  and  weakness.  The  concentrated  gas  may  pro- 
duce an  immediate  fatal  result  by  closure  of  the  glottis  and 
asphyxia.  The  peculiar  odor  and  color  of  the  fumes  aid  in  the 
diagnosis.  Weak  ammonia  by  inhalation  is  the  antidote.  Fresh 
air  and  rest  are  most  important.  Congestion  of  the  lungs  should 
be  relieved,  if  necessary,  by  counter-irritants. 

Alkaline  vapors,  such  as  strong  ammonia,  produce  the  same 
symptoms  as  acid  vapors,  with  perhaps  more  burning  in  the 
throat  and  with  vomiting  and  giddiness.  Vinegar  inhalations 
are  antidotal.  Otherwise  the  treatment  is  the  same  as  for  acid 
gases. 

NEUROTICS. 

The  members  of  this  class  act  principally  on  the  nervous 
system,  after  absorption,  the  symptoms  usually  beginning  in 
about  a  half-hour.  The  class  is  variously  divided  into  several 
varieties,  the  simplest  arrangement  being  into  narcotics,  de- 
pressants, and  convulsants. 


NARCOTICS.  351 


NARCOTICS. 

These  are  characterized  chiefly  by  stupor,  delirium,  and 
insensibility,  the  latter  supervening  in  from  five  minutes  to 
many  hours.  Convulsions  may  occur.  The  treatment  in  gen- 
eral for  narcotic  poisoning  is  to  give  as  an  antidote  for  all  the 
alkaloids  tannic  acid  or  strong  green  tea,  or  potassium  perman- 
ganate grain  for  grain  of  the  poison  (the  stomach  may  be 
washed  with  a  solution  of  permanganate,  2  to  4  grains  to  the 
pint).  Charcoal  is  also  of  some  service  as  an  antidote.  The 
physiologic  antagonists  most  indicated  are  caffein  (or  strong 
coffee  by  the  rectum  or  mouth),  atropin  (Vi2o  grain  every  fifteen 
minutes  for  three  doses  in  morphin  or  opium  poisoning),  am- 
monia, strychnin,  brandy,  and  amyl  nitrite  for  heart-failure; 
morphin  (till  pupils  begin  to  contract)  and  pilocarpin  (l/2  grain) 
for  belladonna,  atropin,  or  other  solanaceous  poisons;  and 
faradism  of  the  phrenic  nerve  in  the  neck.  The  stomach  should 
be  emptied  with  tube,  pump,  or  emetics  (mustard  is  very  good). 
Slap  the  chest  with  towels  wrung  from  cold  water;  apply  cold 
to  the  head  and  warmth  to  the  extremities.  Keep  the  bladder 
empty  to  prevent  resorption  of  the  poison.  Artificial  respira- 
tion may  be  needed  for  a  time.  In  opium  poisoning  the  patient 
should  be  kept  awake  by  walking  him  about.  For  alarming 
symptoms  during  anesthesia  invert  the  patient,  hold  up  the 
base  of  the  tongue,  clear  the  fauces,  inject  stimulants,  use 
nitrite  of  amyl  by  inhalation,  and  employ  artificial  respiration. 
Atropin  and  caffein  are  the  most  generally  useful  stimulants. 

Opium  poisoning  may  take  place  by  way  of  morphin,  co- 
dein,  laudanum,  paregoric,  soothing  and  cough  syrups,  poppy- 
tea,  Dover's  powder,  black  drop,  Godfrey's  cordial,  McMunn's 
elixir,  etc.  One  grain  of  morphin  by  the  mouth,  4  grains  of 
opium,  and  2  drams  of  laudanum  have  each  proved  fatal.  The 
usual  fatal  period  is  from  three  to  twelve  hours,  the  earliest 
having  been  forty-five  minutes.  The  leading  symptoms  are 
staggering,  excitement,  then  coma;  pin-point  pupils  (may  be 
dilated  toward  fatal  end);  slow,  full  pulse,  becoming  weak  and 
irregular;  slow,  stertorous  breathing,  becoming  feeble  and  of 
the  Cheyne-Stokes  type.  The  face  is  congested,  becoming 
paler;  the  skin  is  cold  and  clammy  and  may  show  urticaria  or 
itching.  Convulsions  are  common  in  children,  and  may  be 
tetanic  in  nature.  Children  are  particularly  susceptible  to 
opiates. 

Belladonna  or  atropin  poisoning  exhibits  symptoms  which 
are  almost  entirely  opposite,  namely:  dilated  pupils  and  rapid 
pulse  and  respiration.  There  is  active  delirium;  sometimes 


352  TOXICOLOGY. 

high  fever;  hot,  dry  skin,  throat,  and  fauces;  and  may  be 
strangury  and  suppressed  urine.  A  drop  of  the  patient's  urine 
instilled  into  the  eye  of  a  dog  or  cat  will  dilate  the  pupil  in  a 
few  minutes.  One-half  grain  of  atropin  has  caused  death. 
Poisoning  by  hyoscyamus,  stramonium,  or  solanum  (potato- 
sprouts)  shows  similar  symptoms.  Hyoscin  is  a  muscular 
paralyzant.  Stramonium  excites  cardiac  irregularity  and  furi- 
ous delirium. 

Cannabis-Indica  preparations  have  never  caused  death,  but 
often  produce  alarming  symptoms,  particularly  dilated  pupils 
and  exaltation  of  the  senses.  Minutes  seem  hours,  and  there 
may  be  joyous  delirium  or  double  consciousness.  In  addition 
to  brandy  and  strychnin,  lemon-juice  freely  is  advocated. 

Muscarin  is  the  active  principle  of  poisonous  mushrooms 
or  toad-stools.  These,  when  swallowed,  produce  gastro-en- 
teritis;  vertigo;  dim  vision;  marked  myosis;  intense  dyspnea; 
feeble,  rapid  pulse;  marked  delirium;  tremors,  epileptiform 
attacks;  lethargy,  and  coma.  Pieces  of  the  fungi  may  be 
found  in  the  vomit.  Death  may  occur  in  from  two  to  one 
hundred  hours.  Emetics  and  warm  water  to  aid  vomiting, 
castor-oil  and  enemata,  tannin,  atropiri,  and  coffee  will  do  the 
most  good. 

Alcoholic  coma  is  manifested  by  gradual  stupor;  snoring 
breathing;  fixed,  dilated  pupils;  and  a  ghastly,  suffused,  or 
bloated  face,  with  livid  lips.  There  is  an  alcoholic  or  ethereal 
odor  of  the  breath.  Two  and  one-half  ounces  have  proved  fatal 
in  from  six  to  ten  hours.  Ammonium  carbonate,  capsicum,  and 
coffee  are  of  special  value. 

Chloral  poisoning  ("knock-out  drops")  is  manifested  by 
complete  muscular  relaxation;  slow,  feeble,  irregular  pulse  and 
breathing  (sometimes  stertorous);  subnormal  temperature;  pale 
or  livid  face;  abolished  reflexes;  and  an  odor  like  bananas 
or  pears.  Chloral  heated  with  caustic  alkali  yields  the  odor  of 
chloroform.  Death  has  been  caused  by  7  V2  grains  of  the  hy- 
drate in  from  a  few  minutes  to  a  day.  Aromatic  ammonia, 
strychnin,  coffee,  brandy,  and  amyl  nitrite  are  useful  agents. 
Mustard  plasters  may  be  used  over  the  heart  and  the  calves  of 
the  legs.  Artificial  respiration  should  be  kept  up  for  hours,  if 
necessary. 

Test  for  Chloral. — Take  */,  test-tubeful  of  the  urine";  add  a  drop 
of  anilin  oil  and  a  finger-breadth  of  an  alcoholic  solution  of  NaHO. 
Heat,  and,  if  chloral  be  present,  the  disagreeable  odor  of  isocyanphenyl 
is  noted. 

Death  by  chloroform  inhalations  is  due  apparently  to 
vasomotor  paralysis.  Sudden  marked  dilation  of  the  pupils, 


NARCOTICS.  353 

not  reacting  to  light,  is  a  danger-signal  of  importance.  The 
breathing  becomes  shallow  and  the  pulse  feeble  and  frequent. 
As  little  as  15  minims  has  caused  sudden  death  in  persons  with 
weak  heart.  By  the  mouth  a  dram  has  caused  death  in  a  boy 
of  four  years.  Atropin  is  of  special  service  in  stimulating  the 
sympathetic.  Sodium  bicarbonate  is  the  antidote  for  poisoning 
by  the  mouth. 

Death  under  ether  is  generally  from  asphyxia,  indicated  by 
shallow  breathing,  rapid  pulse,  and  cyanosis.  The  pupils  are 
usually  dilated.  An  ounce  has  caused  death.  The  most  impor- 
tant indications  are  to  clear  the  throat  of  mucus  and  employ 
artificial  respiration. 

Large  doses  of  camphor  may  excite  toxic  symptoms,  such 
as  burning  pain  in  throat  and  stomach;  foaming  at  the  mouth; 
cold,  clammy  skin;  retained  urine;  disturbed  vision;  tinnitus; 
paresis;  delirium;  convulsions,  and  coma.  Three  drams  have 
caused  death.  Stimulants,  warmth  to  the  extremities,  and  hot 
and  cold  douches  are  specially  indicated. 

A  large  proportion  of  C02  in  the  respired  air  causes  giddi- 
ness, ringing  in  the  ears,  irritation  of  the  throat,  loss  of  mus- 
cular power,  feeble  pulse  and  breathing,  and  coma.  The  pure 
gas  terminates  life  instantly  by  apnea  (asphyxia)  from  spasm 
of  the  glottis.  C02  is  classified  as  a  negative  narcotic,  suffoca- 
tive  poison.  The  main  point  in  the  management  of  these  cases 
is  removal  of  the  patient  into  the  fresh  air  and  the  use  of  arti- 
ficial respiration  if  the  symptoms  demand. 

Carbon  monoxid  (coal-gas,  water-gas)  is  a  deadly  narcotic 
poison,  driving  out  oxygen  and  combining  with  the  hemoglobin 
of  the  blood,  which  in  extreme  cases  becomes  of  a  markedly 
bright-red  appearance.  Small  quantities  or  the  gas  produce 
headache,  vertigo,  muscular  weakness,  and  nausea.  A  fatal 
termination  is  preceded  by  asphyxia,  local  paralyses,  subnormal 
temperature,  convulsions,  and  unconsciousness.  The  treatment 
is  not  often  successful,  and  includes  removal  into  the  fresh  air 
and  slapping  the  chest  with  wet  towels,  or  resort  to  artificial 
respiration.  Transfusion  of  blood  from  another  person  should 
improve  the  chance  of  recovery.  CO  is  the  active  agent  in  the 
so-called  charcoal  poisoning  practiced  by  suicides  in  France. 
One  per  cent,  in  the  atmosphere  is  dangerous. 

Sewer-gas  is  a  narcotic  poison,  and  more  than  1  per  cent, 
in  the  atmosphere  may  prove  fatal.  The  symptoms  are  nausea, 
vomiting,  pains  in  the  abdomen  and  extremities,  vertigo,  paresis, 
convulsions,  and  insensibility.  The  best  treatment  is  removal 
into  fresh  air  and  the  use  of  stimulants  as  needed. 

Formaldehyd,  when  freely  inhaled  or  swallowed,  produces 


354  TOXICOLOGY. 

mucous  congestion,  unsteady  gait,  and  sometimes  coma.  For 
poisoning  by  inhalation,  ammonia  cautiously  inhaled  is  recom- 
mended. When  formalin  has  been  swallowed,  the  treatment  is 
the  same  as  for  acute  alcoholic  poisoning. 

DEPRESSANTS. 

Depressants,  or  hypostheniants,  are  marked  especially  by 
feeble  pulse  and  breathing,  and  cause  death  by  paralysis  of  the 
heart  or  respiratory  center.  Insensibility  does  not  come  on 
until  C02  narcosis  supervenes.  All  depressants  except  the 
cyanogen  compounds  have  as  antidotes  tannic  acid  or  strong 
green  tea.  Hypodermics  of  strychnin,  brandy,  aromatic  am- 
monia, ether,  digitalin,  and  atropin,  and  the  administration  of 
strong  coffee  arid  amyl-nitrite  inhalations  are  in  order.  The 
recumbent  posture  should  be  strictly  maintained.  Artificial 
respiration  may  be  required.  Mustard  poultices  to  the  pericar- 
dium do  good.  The  patient  should  be  kept  warm.  Faradization 
or  galvanization  of  the  respiratory  muscles  is  recommended  by 
some  authorities. 

Hydrocyanic  acid  and  substances  containing  it  (cyanids, 
cherry-laurel,  oil  of  bitter  almonds,  wild-cherry  bark,  cassava, 
pits  of  stone-fruit,  etc.)  produce  almost  immediate  salivation; 
constricted  throat;  giddiness;  falling;  insensibility;  convul- 
sions; glassy,  protruded  eyes;  sobbing  or  stertorous  breathing; 
frothing  at  the  mouth;  coldness,  and  collapse.  The  acid  itself 
usually  kills  in  fifteen  to  thirty  minutes.  Death  has  followed 
the  ingestion  of  30  minims  of  the  official  acid,  2  1/2  grains  of 
KCN,  and  20  minims  of  oil  of  bitter  almond.  The  peach- 
blossom  odor  of  HCN"  and  cyanids  is  very  characteristic.  A 
watch-glass  with  a  drop  of  AgN03  solution  adhering  to  it,  when 
held  before  the  mouth  of  the  patient  may  show  a  white  film 
of  AgCN.  Whatever  is  to  be  done  must  be  done  quickly. 
Empty  the  stomach  immediately;  slap  the  chest  with  a  wet 
towel;  use  artificial  respiration;  inject  atropin,  strychnin,  or 
ether;  and  use  amyl  nitrite  or  ammonia  by  inhalation.  Chlorin- 
water  and  calcium  chlorid  are  mentioned  as  antidotes.  For  the 
cyanids,  which  are  somewhat  slower  in  action,  a  mixture  of 
ferric  and  ferrous  sulphates  with  sodium  carbonate  might  be 
of  service. 

Nitrobenzene  (oil,  or  essence,  of  mirbane)  is  like  prussic 
acid  in  action,  but  much  slower.  It  is  marked  by  cyanosis, 
Cheyne-Stokes  breathing,  and  apoplectiform  coma.  The  drug 
smells  like  oil  of  bitter  almonds,  but  does  not  turn  crimson  with 
sulphuric  acid.  Fifteen  grains  have  been  fatal  in  from  four  to 


DEPRESSANTS.  355 

twenty-four  hours.  The  treatment  is  the  same  as  for  H(M 
poisoning. 

The  nicotin  of  tobacco  produces  nausea,  vomiting,  purging, 
pallor,  giddiness,  slow  pulse,  great  depression,  tremors,  cold 
sweats,  contracted  pupils,  and  tetanic  or  clonic  convulsions. 
There  is  a  strong  tobacco-odor  about  the  patient;  nicotin  itself 
is  colored  blood-red  or  brown  by  chlorin.  One  minim  of  nicotin 
has  proved  fatal,  the  period  of  death  being  from  five  minutes 
to  an  hour  or  more. 

Lobelia  and  its  preparations  give  rise  to  symptoms  very 
similar  to  those  produced  by  tobacco,  but  there  is  more  nar- 
cotism. The  peculiar  heavy,  unpleasant  odor  of  the  plant  may 
be  noted.  One  ounce  of  the  leaves  has  led  to  a  fatal  result. 

The  fresh  leaves  of  conium  (hemlock)  have  been  mistaken 
for  parsley.  It  causes  gastric  irritation;  vertigo;  diplopia; 
ptosis;  slow,  labored  breathing;  dilated  pupils;  drowsiness; 
staggering;  motor  paralysis;  dysphagia;  aphonia,  and  as- 
phyxia. It  has  a  peculiar  odor.  The  fatal  dose  of  coniin  is 
1  minim;  period,  one  to  three  hours. 

Cocain  poisoning  is  accompanied  by  a  small,  rapid,  inter- 
mittent pulse;  slow,  shallow  breathing;  a  sense  of  tightness 
about  the  chest;  dilated  pupils;  cold,  clammy  skin;  hallucina- 
tions; delirium;  convulsions,  and  coma.  The  patient  may 
complain  of  feeling  small  foreign  bodies  under  the  skin.  The 
drug  makes  the  tongue  tingle,  then  anesthetic.  A  solution 
dilates  the  pupil  of  a  cat  or  dog  when  locally  applied.  Less 
than  a  grain  of  the  hydrochlorate  has  caused  death  in  a  few 
minutes  to  several  hours. 

Gelsemium  preparations  produce  vertigo;  diplopia;  ptosis; 
dysarthria;  dilated  pupils;  labored  breathing;  rapid,  feeble 
heart;  extreme  weakness;  wide  anesthesia;  and  perhaps  tetanic 
convulsions.  A  dram  of  the  fluid  extract  has  caused  death  in 
from  one  to  eight  hours.  Morphin  is  specially  indicated. 

Aconite  preparations  find  frequent  use  in  medicines  as 
fever-cures  and  neuralgia  liniments;  the  root  has  been  mis- 
taken for  horse-radish.  Toxic  symptoms  are  burning  and  tin- 
gling of  tongue  and  throat;  numbness  of  finger-tips;  cardialgia; 
weak,  slow  pulse;  nausea  and  vomiting;  coldness;  dilated  pu- 
pils; difficult,  feeble  breathing;  and  very  great  prostration. 
Consciousness  is  retained  to  the  last.  Of  the  tincture,  25 
minims  have  proved  fatal;  of  the  alkaloid,  1/12  grain.  Death 
is  sudden  from  collapse  or  asphyxia  within  three  or  four  hours 
generally.  Atropin,  brandy,  coffee,  strychnin,  and  digitalis  are 
most  helpful.  The  back  and  limbs  may  be  rubbed  with  hot 
towels. 


356  TOXICOLOGY. 

Calabar  bean,  or  physostigma,  and  its  alkaloid  are  distin- 
guished by  the  marked  myosis  they  produce.  Other  symptoms 
are  vertigo;  nausea,  vomiting;  slow,  shallow  respiration;  abol- 
ished reflexes,  and  general  paralysis.  Eserin  gives  a  marked 
red  color  with  bromin-water.  Of  this  alkaloid,  1 1/5  grains 
have  proved  fatal.  Atropin  is  the  physiologic  antagonist. 
Chloral  is  of  use  at  an  early  stage. 

The  arrow-poison,  curare  or  woorara,  produces  a  chill; 
rapid,  weak  pulse;  sighing,  labored  breathing;  fever;  protrud- 
ing eyeballs;  inco-ordination,  and  motor  paralysis.  Injected 
beneath  the  skin  of  a  frog,  it  causes  paralysis  of  the  voluntary 
and  respiratory  muscles.  A  few  grains  have  caused  death  in 
one  and  one-half  hours  or  more.  Alkaline  solution  of  potas- 
sium permanganate  is  of  service  locally. 

The  coal-tar  antipyretics  frequently  lead  to  cyanosis;  slow 
breathing;  feeble,  irregular  pulse;  vomiting;  profuse  sweat- 
ing, and  profound  prostration.  Five  grains  of  acetanilid  have 
caused  death.  Alcohol,  ether,  strychnin,  and  oxygen  inhalations 
are  the  best  stimulants  in  such  cases.  Warmth  should  be  ap- 
plied to  the  feet  and  the  body.  The  symptoms  and  treatment 
of  anilin  poisoning  are  similar. 

Santonin,  used  so  extensively  as  a  vermifuge,  has  caused 
death  in  the  dose  of  2  grains.  The  symptoms  of  poisoning  are 
violet  or  green-yellow  vision,  trismus,  dilated  pupils,  hallucina- 
tions, convulsions,  and  collapse.  The  urine  is  colored  greenish 
yellow;  red,  if  alkaline. 

CONVULSANTS. 

These  are  characterized  chiefly  by  tonic  and  clonic  spasms. 
The  mind  is  usually  clear  till  near  the  end.  Nux  vomica  and 
ignatia  contain  the  alkaloids  strychnin  and  brucin.  The  former 
is  sometimes  used  in  vermin-killers.  It  has  a  very  bitter  taste, 
and  produces  restlessness,  shivering,  shuddering,  epigastric 
pain,  twitching  muscles,  sudden  jerkings  of  the  limbs  and  head, 
and  especially  tonic  spasms  of  the  neck,  back,  chest,  and  dia- 
phragm, followed  by  sweating.  The  resulting  dyspnea  is  marked 
by  a  livid,  congested  face,  which  wears  an  unmeaning  smile 
(risus  sardonicus)  ;  the  eyes  are  staring  and  the  pulse  becomes 
very  rapid  and  feeble.  The  senses  are  extremely  acute,  and  the 
slightest  noise  or  excitement  may  precipitate  a  spasm.  Although 
there  is  a  strange  feeling  in  the  jaw,  this  is  seldom  involved 
in  spasm,  and  then  late  (distinction  from  tetanus).  The  symp- 
toms of  brucin  poisoning  are  similar,  but  slower  and  less 
marked.  One-half  grain  of  strychnin,  30  grains  of  powdered 
nux,  and  3  grains  of  brucin  have  resulted  fatally.  The  period 


CHRONIC  POISONING.  357 

of  death  from  strychnine  is  from  five  minutes  to  six  hours; 
average,,  two  hours.  Tannic  acid  or  hot,  strong  coffee  or  green 
tea  and  charcoal  are  useful  antidotes.  Keep  the  patient  quiet  in 
a  darkened  room;  use  chloroform  or  ether  inhalations  during  the 
paroxysms;  also  artificial  respiration  if  needed.  Chloral  in  milk 
by  the  rectum  is  a  most  efficient  antagonist.  Ice  to  the  spine 
is  of  some  service. 

Picrotoxin,  or  cocculus  Indicus,  sets  up  choreic  spasms 
(mostly  flexor),  giddiness,  lethargy,  delirium,  coma,  and  slow, 
labored  breathing.  It  has  an  intensely  bitter  taste.  Sulphuric 
acid  gives  with  it  an  orange-yellow  color.  Three  grains  of  picro- 
toxin  have  caused  death  in  about  a  half -hour.  The  treatment 
is  the  same  as  for  strychnin. 


CHRONIC    POISONING. 

Chronic  poisoning  is  generally  the  result  of  occupation  or 
environment.  The  continued  absorption  of  metallic  substances 
leads  first  to  neuritis  and  later  paralysis.  The  treatment  in 
general  is  to  remove  the  cause  if  possible;  to  get  rid  of  the 
accumulated  poison  by  the  administration  of  full  doses  of  potas- 
sium iodid  in  plenty  of  water;  and  the  symptomatic  relief  of 
paralysis  and  other  symptoms  by  electricity  and  other  suitable 
measures  as  indicated  in  the  individual  case.  In  the  treatment 
of  lead  poisoning  dilute  sulphuric  acid  and  magnesium  sulphate 
are  administered  to  ppt.  the  poison  excreted  by  the  intestine 
and  eliminate  it  in  this  way.  Injections  of  morphin  and  atro- 
pin  may  be  occasionally  required  to  relieve  pain. 

LEAD. 

Chronic  lead  poisoning  is  seen  most  frequently  in  painters, 
printers,  plumbers,  smelters,  and  founders;  less  frequently  in 
potters,  file-cutters,  leather-cutters,  pewterers,  lace-makers, 
artists,  tinners,  glazers,  glass-grinders,  and  manufacturers  of 
lead  paints,  glass  enamel,  hair-brushes,  oil-cloths,  rubber,  shot, 
sheet-lead,  etc.  It  may  arise  from  drinking-water,  especially 
when  this  is  soft  or  carbonated;  also  from  drinking  acid  liquors 
from  pewter  vessels  or  stop-cocks.  Other  occasional  sources 
are  tin-foil  goods,  chrome-yellow  in  cakes  and  candies;  acid 
canned  goods;  vinegar  and  preserves  kept  in  glazed  earthen 
vessels;  snuff  colored  with  minium  or  chromate;  contamina- 
tion of  flour  by  plugs  of  lead  in  millstones;  contamination  dur- 
ing manufacture  of  acids  and  salts;  leaden  toys;  colored  paper; 


358  TOXICOLOGY. 

false  teeth;  biting  off  thread  weighted  with  white  lead;  use  of 
PbS  as  a  hair-dye,  or  of  carbonate  as  a  cosmetic;  the  use  of 
shot  in  cleaning  bottles;  soda  or  potash  kept  in  flint-glass 
bottles;  hat-linings  glazed  with  white  lead;  lead  plates  in  den- 
tistry; collyria;  vaginal  injections;  sleeping  in  freshly  painted 
rooms. 

The  leading  symptoms  of  plumbism  are  motor  paresis  or 
paralysis,  most  marked  in  the  extensor  muscles  of  the  forearm 
("wrist-drop"  or  "thumb-drop"),  preceded  by  slight  numbness 
and  tremors;  neuralgic  pains  in  the  flexures  of  the  joints; 
amaurosis;  obstinate  constipation,  with  paroxysms  of  twisting, 
grinding  pain  (lead  colic)  in  the  middle  abdomen,  which  is 
usually  depressed  and  board-like;  slow,  full,  hard  pulse;  sallow, 
anemic  pallor;  and  afebrile  encephalopathy  (mental  depression 
and  lassitude,  headache,  dizziness,  disturbed  sleep,  delirium, 
hallucinations,  saturnine  lunacy,  epileptiform  convulsions,  and 
partial  coma). 

A  blue  line  is  sometimes  noted  at  the  intragingival  margin 
of  the  gums  and  teeth,  due  to  a  deposition  of  PbS  in  the  cap- 
illaries. If  a  small  area  of  skin  is  painted  with  6-per-cent. 
sodium  sulphite,  it  will  darken  after  a  few  days.  The  metal  is 
nearly  always  to  be  found  in  the  greatly  concentrated  urine 
(boil  down  with  dilute  nitric  acid),  especially  after  the  admin- 
istration of  KI  for  a  day  or  so. 

ARSENIC. 

Chronic  arsenical  poisoning  may  result  from  continuous 
medication  or  homicidal  administration.  It  also  occurs  among 
smelters,  miners,  furriers,  taxidermists,  naturalists,  manufact- 
uring chemists,  embalmers,  and  dress-makers  (from  green 
tarlatan).  Occasional  sources  of  poisoning  are  from  green  wall- 
paper (from  less  than  a  grain  to  a  dram  per  square  foot),  toys, 
and  candies;  anilin-dyed  lace  and  clothing;  artificial  flowers; 
carpets;  porcelain  lamp-shades;  and  the  internal  use  of  the 
drug  for  cosmetic  effect. 

The  symptoms  of  arsenism  often  simulate  enterocolitis  or 
even  typhoid  fever.  There  is  gastro-intestinal  irritation,  nau- 
sea, vomiting,  and  diarrhea;  conjunctivitis  and  edematous  puff- 
ing of  the  lower  lids;  squamous  or  vesicular  eruptions;  grad- 
ually increasing  diffuse  multiple  neuritis  (numbness  and  tin- 
gling of  fingers  and  toes,  darting  pains  in  limbs  and  continuous 
pain  in  joints),  followed  by  local  (rarely  general)  pareses  and 
paralyses,  chiefly  of  the  leg-extensors  and  peroneal  group,  caus- 
ing "steppage  gait."  Albuminuria  is  common,  and  arsenic  may 


CHRONIC  POISONING.  359 

be  detected  in  the  urine  by  Marsh's,  test  after  oxidizing  all  or- 
ganic matter.  Sudden  death  from  heart  weakness  is  observed 
in  habitues. 

MERCUEY. 

Hydrargyrism  is  observed  among  quicksilver  miners, 
smelters,  gilders,  hatters,  furriers,  bronzers,  photographers, 
and  manufacturers  of  barometers,  thermometers,  amalgams, 
artificial  teeth,  and  vermilion  pigment.  It  may  also  arise  from 
fillings  in  teeth  or  from  medication.  The  most  characteristic 
symptom  of  chronic  mercurial  poisoning  is  the  "intention 
tremors"  (aggravated  by  motion),  followed  by  paralysis  ("shak- 
ing palsy"),  extending  gradually  from  the  upper  extremities  to 
all  the  muscles  of  the  body.  Another  important  and  early 
symptom  is  ptyalism,  accompanied  by  sore  and  swollen  gums 
and  very  offensive  breath,  and  rarely  followed  by  falling  out  of 
teeth  and  maxillary  necrosis.  The  poison  can  be  detected  in 
the  urine  the  next  day  after  giving  KI.  Acidulate  urine  with 
HC1,  add  Cu  filings,  heat  for  five  minutes  at  50°  to  60°  C.,  and 
let  stand  till  cool.  Wash  filings,  transfer  to  a  shallow  dish,  and 
invert  over  this  a  watch-glass  having  on  its  under-surface  1 
drop  of  1-per-cent.  AuCl3  solution.  On  heating  over  a  low 
flame  the  Hg  film  on  the  Cu  will  volatilize  and  redden  the  Au- 
C13.  This  test  is  said  to  react  with  1  part  of  Hg  in  10,000,000. 


COPPER. 

Chronic  copper  or  brass  poisoning  has  been  noted  among 
artisans  who  work  in  these  metals.  It  may  also  occur  from 
keeping  food  in  dirty  copper  vessels  or  from  color  adulterations. 

The  subjects  of  this  condition  complain  of  an  acrid, 
styptic,  coppery  taste;  of  a  dry,  parched  tongue;  heat  and  con- 
striction of  the  throat;  and  continuous  spitting.  There  is 
sometimes  a  greenish  or  purple  line  at  the  gum-margins; 
colicky  pains  and  abdominal  tenderness;  and  bloody,  greenish 
diarrhea,  with  tenesmus.  Greenish  perspiration  has  been  ob- 
served in  the  hairy  parts.  The  metal  can  generally  be  isolated 
from  the  urine. 

ANTIMONY. 

Chronic  antimonial  poisoning  may  be  caused  by  medication 
or  homicidal  administration.  There  is  great  depression;  clammy 
sweats,  distressing  nausea,  with  occasional  mucous  and  bilious 


360  TOXICOLOGY. 

vomiting,,  dyspnea,  and  a  small,  frequent  pulse.     The  urine  is 
increased  in  quantity  and  shows  the  poison  with  Marsh's  test. 


SILVER, 

Argyria  rarely  occurs  nowadays  from  the  protracted  ad- 
ministration of  silver  salts,  and  has  also  been  noted  in  persons 
engaged  in  silvering  glass.  The  characteristic  sign  is  a  per- 
manent olive,  slaty,  or  gray-brown  coloration,  beginning  in  the 
conjunctiva,  around  the  nails,  and  the  inside  of  the  lips.  It  is 
irremediable,  and  is  due  to  decomposition  of  Ag  salts  in  the 
tissues  exposed  to  light,  with  deposition  of  the  metal.  Promi- 
nent nervous  symptoms  are  inco-ordination,  tetanic  convulsions, 
and  wide-spread  paralysis,  without  loss  of  electromuscular  irri- 
tability. 

PHOSPHORUS. 

Chronic  phosphorus  poisoning  is  seen  among  people  en- 
gaged in  the  manufacture  of  matches  with  white  phosphorus. 
The  chief  lesion  is  periostitis  of  the  jaw,  followed  by  caries  of 
teeth  and  necrosis  of  the  bone.  Carious  teeth  predispose. 
Gastro-enteritis,  joint  pains,  peripheral  palsies,  jaundice,  hectic 
fever,  chronic  bronchial  catarrh,  and  peptonuria  may  be  present. 
Oil  of  turpentine  and  alkaline  mouth-washes  may  help  to  pre- 
vent necrosis. 

ALCOHOL. 

Chronic  alcoholism  is  marked  by  chronic  gastric  catarrh, 
with  furred  tongue  and  morning  vomiting.  Peripheral  neuritis 
and  fine  tremors  of  the  hands  and  tongue  (worse  mornings  be- 
fore a  drink)  are  also  noted,  as  well  as  a  marked  moral  change. 
The  small  veins  of  the  nose  and  cheek  are  dilated,  and  the  eyes 
are  red  and  watery.  Delirium  tremens  is  sometimes  precipi- 
tated by  trauma  or  acute  fevers,  particularly  pneumonia.  He- 
patic cirrhosis,  granular  kidney,  fatty  heart  and  liver,  and  a 
special  liability  to  phthisis  and  acute  infections  are  among  the 
effects  of  the  long-continued  use  of  alcohol. 


TOBACCO. 

Smoking  is  more  likely  to  excite  toxic  symptoms  than 
chewing.  Among  the  most  important  symptoms  of  chronic 
tobacco  poisoning  are  cardiac  palpitation  and  false  angina  pec- 


CHRONIC  POISONING.  361 

toris,  rapid  or  intermittent  pulse,  granular  inflammation  of  the 
fauces  and  pharynx,  tremors,  giddiness,  nervous  depression, 
sclerosis  of  middle  ear,  and  amaurosis  or  fluttering  scotoma  and 
color-blindness.  The  dryness  of  the  throat,  from  the  caustic 
action  of  the  potash  in  the  leaf,  favors  dyspepsia  and  alcoholism. 


MORPHIN  OR  OPIUM. 

The  morphin  or  opium  habit  may  be  developed  even  in 
young  infants  from  sucking  an  habitue  or  from  the  continued 
use  of  soothing  syrups.  The  signs  of  addiction  are  chiefly 
progressive  asthenia;  disturbed  sleep;  mental  depression; 
moral  perversion;  haggard  countenance;  dry,  harsh  skin  (often 
needle-scarred);  deranged  appetite  and  digestion;  precordial 
distress;  occasional  profuse  sweats,  preceded  by  chills  and 
fever;  and  sexual  perversions  and  impotence.  An  important 
point  in  diagnosis  is  the  marked  improvement  in  the  subjective 
symptoms  on  giving  another  dose  of  the  drug. 


CHLORAL. 

The  chloral  habit  causes  impairment  of  intellection,  will, 
and  memory;  silly  excitability  and  volubility;  persistent  drow- 
siness (very  wakeful  without  drug);  sensory  disturbances; 
anemic,  but  flushed,  face;  erythema  of  skin  of  fingers,  with  ul- 
ceration  around  nails;  feeble,  irregular,  irritable  heart;  and 
polyuria,  often  stained  with  bile.  This  drug  may  cause  de- 
lirium tremens. 

COCAIN, 

A  cocain  "fiend"  is  often  the  result  of  patent  "catarrh 
cures"  or  of  the  attempt  to  substitute  this  drug  for  morphin. 
Hyperesthesia  of  the  special  senses,  especially  of  hearing,  is  a 
prominent  symptom.  There  is  absolute  insomnia  or  hypnosis, 
and  lewd  hallucinations  and  delusions.  The  facies  is  pallid, 
yellow,  and  care-worn;  the  breath  very  fetid;  the  skin  bathed 
with  perspiration.  Hydruria  and  sometimes  incontinence 
obtain. 

ERGOT. 

Chronic  ergotism  occurs  from  eating  bread  containing  the 
fungus  of  rye  and  darnel.  The  affection  is  sometimes  epidemic 
in  Spain  and  Russia.  The  prolonged  use  of  the  drug  medic- 
inally may  also  act  as  a  cause.  The  patient  complains  of  dis- 


362  TOXICOLOGY. 

turbances  of  special  and  general  sensation;  of  pain  in  the  back 
and  painful  muscular  cramps;  of  chilly  sensations  and  night- 
sweats.  The  skin  is  pale  or  earthy,  and  dry  gangrene  of  fingers 
and  toes  appears  in  the  gangrenous  form.  The  temperature  is 
subnormal.  Epileptoid  flexor  spasms  and  sometimes  gradual 
loss  of  tendon-reflexes  may  take  place. 


DAMAGED  MAIZE. 

Maidismus,  or  pellagra,  is  confined  to  southern  Europe  and 
is  nearly  always  epidemic.  It  is  due  to  the  fungus,  Reticularia 
ustilago.  The  most  marked  sign  of  the  disease  is  a  diffuse 
erythema  in  the  first  stage;  turning  to  marked  pallor  or  patches 
of  capillary  congestion  in  the  second;  and  in  the  third  stage  the 
skin  becomes  dry,  shriveled,  and  dark  brown,  with  exfoliation 
and  suppuration. 

TEA  AND  COFFEE. 

Men  and  women  who  drink  much  tea  complain  of  flushings, 
insomnia,  restlessness,  headache,  vertigo,  tinnitus,  flashes  of 
light,  mental  dullness,  and  confusion.  They  are  mentally 
exhausted  and  apprehensive  of  evil  and  disinclined  to  mental 
exertion.  The  heart's  action  is  increased  and  irregular.  Mus- 
cular tremor,  hyperesthesia,  and  paresthesia  are  sometimes 
noted.  Chronic  coffee  intoxication,  such  as  is  observed  in 
Brazil,  is  marked  by  a  state  of  constant  wakefulness  and  excite- 
ment and  digestive  and  cardiac  disturbances.  Coffee  addiction 
is  particularly  injurious  to  children,  because  of  its  excessive 
stimulation  of  the  nervous  system. 


IODISM. 

The  administration  of  iodids  in  excess  leads  to  running  at 
the  nose,  sore  throat,  bronchitis,  salivation,  gastric  irritation, 
erythematous  patches,  heavy  pain  over  the  frontal  sinus,  neu- 
ralgia and  tinnitus  aurium,  and  even  convulsive  movements. 
Rapid  emaciation  may  occur. 


BROMISM. 

Taking  bromids  for  too  long  a  period  causes  a  general  low- 
ering of  cutaneous  and  pharyngeal  sensibility,  mental  depres- 
sion, dulled  intellection,  and  inability  to  work  with  the  brain. 


POISONOUS  BITES  AND  STINGS.  363 

The  tongue  is  coated  and  the  digestion  disordered.  Quite  often 
there  is  an  eruption  of  red  acneiform  papules,  mostly  on  the 
face  and  back. 

CYANOGEN. 

Chronic  cyanogen  poisoning  is  observed  among  photog- 
raphers and  gilders.  It  is  characterized  by  headache,  vertigo, 
tinnitus,  throat  constriction,  indigestion,  constipation,  dyspnea, 
and  precordial  pain.  The  face  is  pale,  the  pulse  full,  and  the 
breath  offensive. 

CARBON  DISULPHID. 

Chronic  poisoning  by  this  substance  is  noted  in  the  manu- 
facturers of  rubber  goods.  There  is  a  stage  of  excitement,  fol- 
lowed by  depression.  The  symptoms  are  chiefly  nervous,  and 
include  headache;  irritability;  debility;  tinnitus;  formication; 
hyperesthesia,  followed  by  anesthesia;  insomnia;  sometimes 
monospasm,  monoplegia,  or  paraplegia;  and  especially  pains  in 
the  limbs. 

CHROMIUM. 

Men  who  make  potassium  dichromate  are  often  troubled 
with  obstinate  sores  on  their  hands.  These  sores  slough,  form- 
ing a  deep,  foul  ulcer,  with  hard  edges. 


POISONOUS    BITES    AND    STINGS. 

The  venom  that  passes  from  the  poison-gland  of  a  dan- 
gerous reptile  through  the  hollow  fang  into  the  wound  made 
by  a  bite  quickly  causes  the  part  bitten  to  become  dark,  swollen, 
and  very  painful.  The  chief  general  symptom  is  prostration; 
but  dyspnea,  jaundice,  cold  sweats,  bilious  vomiting,  delirium, 
and  convulsions  may  occur.  The  wound  should  be  promptly 
drained  by  incision  and  cupping  or  sucking.  There  is  no  danger 
in  sucking  out  snake-venom  or  even  in  swallowing  it,  providing 
there  are  no  cracks  in  the  mucous  membrane  about  the  lips  and 
tongue.  The  local  injection  of  liquor  ammonia  and  of  a  strong 
solution  of  potassium  permanganate  or  calcium  chlorid  is  rec- 
ommended by  various  authorities.  An  intermittent  ligature 
should  be  applied  above  the  wound  to  prevent  as  much  as 
possible  the  introduction  of  the  poison  into  the  general  cir- 
culation. Alcoholics,  strychnin,  atropin,  and  other  stimulants 
should  be  administered  in  full  doses,  but  not  ad  libitum.  Cal- 


364  TOXICOLOGY. 

mette's  antivenene,  in  frequently  repeated  injections  of  10  to 
20  c.c.,  has  saved  life  when  used  promptly.  The  poison  of 
venomous  reptiles  consists  essentially  of  a  pepton  and  a  glob- 
ulin. 

The  bite  of  a  rabid  dog  is  likely  to  lead  in  a  few  weeks  to 
the  development  of  hydrophobia.  Thorough  excision  of  the 
entire  wound  area  is  the  safest  procedure  in  these  cases.  Next 
best  is  to  encourage  free  bleeding  and  then  to  cauterize  the 
wound  thoroughly  with  strong  HN03,  neutralizing  any  excess 
with  baking-soda  or  ammonia.  The  acid  is  more  penetrating 
in  its  action  than  silver  nitrate,  commonly  used  for  this  pur- 
pose. 

The  sting  of  bees  and  ants,  and  more  especially  wasps  and 
hornets,  may  lead  to  erysipelatous  swelling,  suppuration,  gan- 
grene, and  even  death.  The  treatment  is  to  remove  the  poison 
as  much  as  possible  by  wet-cupping,  then  neutralize  the  acid 
present  in  the  poison  with  ammonia  or  baking-soda.  The  mere 
application  of  one  or  other  of  these  is  usually  sufficient  in  mild 
cases. 

QUESTIONS  ON  TOXICOLOGY. 

1.  Explain  the  principle  of  the  ligature  in  cases  of  snake-bite. 

2.  How  may  a  small  dose  of  arsenic  prove  fatal,  while  a  larger 
one  does  not? 

3.  How  distinguish  between  antemortem  and  post-mortem  imbibi- 
tion of  poisons  by  the  viscera? 

4.  A  body  dead  for  some  weeks  shows  yellow  stains  in  the  viscera 
from  arsenic;   red  from  antimony;   black  from  mercury.     Explain. 

5.  Bodies  have  been  exhumed  some  years  after  burial  and  found 
in  a  good  state  of  preservation.     What  poison  should  be  suspected? 

6.  What  is  the  antidote  for  concentrated  lye? 

7.  Explain  curdy  vomit  in  poisoning  by  silver  or  lead  salts. 

8.  In    a    certain    case    of    poisoning    a    blue    vomit    was    noticed. 
Explain. 

9.  Write  equation  for  the  antidotal  reaction  of  ferric  hydrate  with 
arsenous  oxid. 

10.  What  common  syrup  may  be  the  source  of  antimonial  poison- 
ing? 

11.  Name  six  common  household  antidotes  and  their  special  uses. 

12.  What  causes  the  yellow  staining  of  the  tissues  in  nitric-acid 
poisoning? 

13.  In  a  case  of  poisoning  white  fumes  are  produced  by  dipping  a 
glass  rod  in  HC1  and  holding  it  near  the  mouth.     Explain. 

14.  Explain   antidotal    effect   of   sodium    hyposulphite   with    hypo- 
chlorites. 

15.  Why  should  fats  and  oils  be  avoided  in  poisoning  by  phenol  or 
phosphorus? 

16.  What  acid  chars  the  tissues  and  stomach-contents? 

17.  What  gaseous  poison  accumulates  in  and  around  beer- vats? 

18.  What  dangerous  poison  is  sometimes  given  out  from  red-hot 
base-burner  stoves? 


QUESTIONS.  365 

19.  What  possible  danger  is  there  from  the  use  of  carbonates  and 
bicarbonates  as  antidotes  for  mineral  acids? 

20.  How  prove  the  presence  of  P  in  match-heads? 

21.  Name  five  poisons  that  may  cause  fever. 

22.  Compare  the  symptoms  of  opium  and  belladonna  poisoning. 

23.  Compare  the  symptoms  and  treatment  of  poisoning  by  corrosive 
acids  and  by  caustic  alkalies. 

24.  Mention  the  chief  points  in  the  diagnosis  of  the  poison  taken 
gained  by  looking  into  the  patient's  mouth. 

25.  What  effect  would  a  hot-sulphur  bath  have  on  a  person  who 
has  been  "leaded"? 


PHYSIOLOGIC  AND  PATHOLOGIC 
CHEMISTRY. 


CHEMIC     COMPOSITION     OP     THE 
HUMAN    BODY. 

OF  the  21  elements  found  normally  in  the  human  body, 
17  are  constantly  present.  C  (13  V2  per  cent.),  H  (9  per  cent.), 
N  (2  V2  per  cent.),  and  0  (72  per  cent.)  constitute  97  per  cent., 
by  weight,  of  the  body,  chiefly  in  combination,  though  the  last 
three  also  occur  free  in  the  blood,  stomach,  and  intestines,  N 
and  0  being  inhaled  or  swallowed  and  H  arising  from  putre- 
factive processes. 

The  following  elements  are  likewise  essential  body  ingre- 
dients in  the  percentages  mentioned:  Ca,  1.3;  P,  1.15;  S',  1/7 
of  1  per  cent.;  Na,  0.1;  Cl  and  F,  each,  l/ia  of  1  per  cent.;  K, 
V40  of  1  per  cent.;  Mg,  1/80  of  1  per  cent.;  Fe,  0.01  (3  gm. 
altogether);  Si,  Vsoo  of  1  per  cent.;  Mn,  0.0005  per  cent.; 
and  I,  a  trace.  Na  is  present  chiefly  in  the  fluids  of  the  body, 
which  it  renders  alkaline,  while  K  occurs,  for  the  most  part, 
in  the  solid  tissues,  because  membranes  absorb  it  better.  S 
occurs  as  taurin  in  the  muscles  and  bile,  as  H2S  in  the  feces, 
and  as  sulphates  in  the  urine.  Fe  is  the  coloring  matter  of 
blood,  bile,  hair,  and  skin  pigment.  It  has  great  affinity  for  0, 
which  it  carries  from  the  lungs  to  the  tissues.  It  is  present 
in  the  liver  as  the  organic  compounds  ferratin  and  hepatin. 

A  considerable  trace  of  I  is  met  with  in  the  thyroid.  It 
seems  to  exert  an  antitoxic  action  and  to  increase  the  metab- 
olism of  proteins.  A  deficiency  of  thyroidin  leads  to  the  pecul- 
iar disease  myxedema.  Traces  of  Mn,  As,  Cu,  Pb,  Al,  and  Br 
are  occasionally  encountered  in  the  liver,  which  acts  as  a  buffer 
for  the  rest  of  the  system,  protecting  it  from  poisoning  from 
without  and  from  within. 

Of  the  inorganic  compounds  that  help  to  make  up  the 
body,  H20  is  most  abundant,  constituting  67.6  per  cent.,  by 
weight,  of  the  whole,  and  ranging  from  0.4  per  cent,  in  the 
enamel  of  teeth  to  99.5  per  cent,  in  saliva.  Water  is  the  sys- 
tem solvent  for  absorption,  secretion,  and  excretion.  It  makes 
the  tissues  soft,  flexible,  and  elastic,  and  by  evaporation  aids  in 
(366) 


CHEMIC  COMPOSITION  OF  BODY.  367 

regulating  animal  heat.  About  a  pound  of  H20  is  formed 
daily  in  the  body  by  the  oxidation  of  H  compounds.  A  loss  of 
5  or  6  per  cent,  of  water,  as  in  cholera,  renders  the  blood  viscid 
and  slow  of  current,  irritating  to  the  nerves,  and  causing  con- 
vulsions. 

The  nascent  H  produced  by  cell-decomposition  probably 
unites  first  with  0,  forming  H202;  and  this  has  been  found  in 
the  sweat  and  other  fluids.  The  peroxid  thus  formed  quickly 
breaks  down  into  H20  and  nascent  0. 

Of  compound  gases,  C02,  H2S,  and  CH4  are  most  impor- 
tant. The  first  is  formed  in  living  cells  by  internal  oxidation, 
and  also  during  fermentation  in  the  alimentary  tract.  It  is 
present  chiefly  in  the  blood  in  combination  with  Na.  H2S, 
formed  by  the  putrefaction  of  S-containing  proteins  (eggs), 
occurs  mostly  in  the  bowels,  but  may  also  be  found  in  old 
abscess-cavities.  CH4  is  derived  from  acetates,  the  fermenta- 
tion of  cellulose,  or  protein  putrefaction,  and  is  the  principal 
gas  giving  rise  to  flatulence  and  colic.  It  is  the  only  hydro- 
carbon found  in  the  body. 

The  chlorid  of  Na  is  present  in  all  the  body-fluids  (0.65 
per  cent,  in  blood-serum),  and  is  of  great  importance  in  pro- 
moting osmosis  and  diffusion.  KC1  is  most  abundant  in  blood- 
corpuscles  and  muscles.  CaCl2  is  also  a  necessary  ingredient 
of  the  blood.  The  chlorids  generally  pass  through  the  body 
unchanged,  except  the  small  proportion  of  NaCl  used  up  in 
making  HC1.  CaF2  is  present  chiefly  in  the  bones  and  teeth, 
especially  the  enamel  (2  per  cent.). 

The  phosphates  of  K,  Na,  Ca,  and  Mg  are  present  in  nearly 
every  tissue  and  fluid  of  the  body,  in  loose  combination  with 
proteid  compounds.  The  alkalinity  of  the  blood  is  due  partly 
to  the  secondary  sodium  phosphate,  Na2HP04,  which  is  partly 
changed  by  C02  to  the  primary  phosphate,  NaH2P04,  to  which 
the  acidity  of  the  urine  is  largely  due.  Fe2(P04)2  is  present  in 
the  bile,  the  gastric  and  intestinal  juices,  and  in  the  pigment 
of  hair  and  epithelium. 

The  carbonate  of  Ca  is  an  essential  component  of  bones 
and  teeth.  The  otoliths  of  the  internal  ear  are  composed  of 
crystalline  CaC03.  The  carbonates  of  K  and  N"a  aid  in  ren- 
dering the  blood  alkaline.  They  take  up  C02,  forming  bicar- 
bonates.  Ammonium  carbonate  is  found  normally  only  in 
traces  in  the  blood.  The  amount  is  greatly  increased  in  cholera, 
with  ammoniacal  breath  and  stools. 

A  small  quantity  of  the  sulphates  of  K,  Na,  and  Ca  is 
found  in  nearly  every  part  of  the  organism.  Very  minute  quan- 
tities of  Si02  are  obtained  from  the  blood,  urine,  bones,  and 


368  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

hair.  NH3  is  produced  in  the  tissues  "by  the  union  of  N  and 
H.  It  combines  with  C02  to  form  ammonium  carbamate,  which 
is  dehydrated  in  the  liver  into  urea. 

The  non-nitrogenous  organic  constituents  of  the  body  in- 
clude CH4,  dextrose,  lactose  (breast-milk),  inosit,  glycogen,  fats,, 
and  fatty  acids. 

Dextrose  is  the  chief  sugar  of  the  blood  and  muscles. 
There  is  at  least  0.1  in  the  blood,  even  during  starvation.  It 
is  derived  mainly  from  starch  and  cane-sugar,  but  is  also  in 
part  a  derivative  of  proteins,  which  may  be  made  to  yield  arti- 
ficially as  much  as  60  per  cent,  of  dextrose. 

Inosit  [C6H6(HO)6]  is  present  in  muscles  and  viscera.  It 
can  be  oxidized  and  utilized  by  diabetics.  Lactose  is  a  leading 
ingredient  of  mothers'  milk  (and  amniotic  fluid),  and  is  likely 
to  be  found  in  the  blood  and  urine  whenever  the  milk-flow  is 
obstructed.  The  glucosid,  jecorin,  found  in  the  liver  and  the 
blood,  yields  dextrose  on  decomposition.  Indican  is  a  brownish, 
bitter,  syrupy  glucosid  derived  from  indol,  a  weak  base  produced 
by  the  pancreas  and  during  intestinal  putrefaction. 

The  body-glycogen  is  about  equally  distributed  in  the  mus- 
cles (0.4  to  0.8  per  cent.)  and  the  liver.  This  supply  is  drawn 
upon  by  hunger.  Muscular  work  also  causes  a  rapid  conversion 
of  glycogen  into  dextrose.  The  glycogen  is  probably  derived 
in  part  from  tissue-proteins. 

The  body-fat  is  all  in  a  fluid  condition,  owing  to  the  con- 
siderable proportion  (67  to  80  per  cent.)  of  olein  with  the 
palmitin  and  stearin.  Lecithin  is  a  waxy,  phosphorized  fat 
present  in  every  living  cell,  and  most  abundant  in  the  brain  and 
nerves.  Boiling  with  acids  or  alkalies  breaks  it  up  into  cholin, 
fatty  acids,  and  glycerophosphoric  acid.  It  swells  in  distilled 
water,  giving  rise  to  the  "myelin  forms"  of  nerve-tissue. 

Protagon  is  obtained  from  the  brain.  It  is  a  crystalline 
body  containing  lecithin  and  cerebrin.  The  latter  is  a  glucosid, 
breaking  up  into  d.  galactose. 

Organic  acids  are  present  chiefly  in  the  excretions  (often 
as  under-oxidation  products)  and  in  fermentation  and  putre- 
faction compounds.  HCOOH  is  found  in  sweat.  The  formates 
are  much  increased  in  the  blood  and  urine  in  fever,  diabetes,, 
leukemia,  and  wood-alcohol  poisoning.  CH3COOH  is  often 
found  in  feces.  When  absorbed  from  the  intestine  it  is  burned 
into  C02  and  H20.  It  is  present  in  the  blood,  sweat,  and  urine  in 
leukemia  and  diabetes.  Diacetic  acid  (CH2CH3COCOOH)  and 
beta-oxybutyric  acid  (CH3.CHOH.CH2COOH)  probably  result 
from  fat-metabolism.  They  are  increased  in  starvation  and 
diabetes,  neutralizing  the  blood  and  causing  coma  and  increase- 


CHEMIC  COMPOSITION  OF  BODY.  369 

of  NH3  in  the  urine.  (CH3)2CO  is  increased  in  the  blood  and 
urine  whenever  there  is  excessive  decomposition  of  fat,  as  in 
diabetes.  C2H5COOH,  from  protein  putrefaction,  is  found  in 
the  sweat,  bile,  and  sometimes  in  the  stomach.  C3H7COOH, 
from  the  putrefaction  of  proteins  and  carbohydrates,  is  found 
in  the  stomach-contents  in  hypochlorhydria,  and  in  the  intes- 
tinal evacuations.  A  bad  taste  in  the  mouth  is  frequently  due 
to  this  acid.  H2C204  is  a  metabolic  product  derived  chiefly 
from  nucleins  and  gelatins. 

The  foul-smelling  isovaleric  acid,  C4H9COOH,  from  pro- 
teid  decomposition,  is  noted  in  sweating  feet  and  sometimes  in 
the  urine  in  certain  grave  diseases.  Capric  and  caprylic  acids 
are  found  in  the  perspiration  and  in  milk-fat;  palmitic,  oleic, 
and  stearic  acids  are  present  in  milk-fat  and  adipose  tissue. 
The  very  slight  acid  reaction  of  bile  is  due  to  these  three  acids. 
C3H603,  from  fermented  milk,  is  of  common  occurrence  in  the 
stools  of  infants.  Sarcolactic  (paralactic,  or  right  ethidene)  is 
found  in  the  muscles,  blood,  and  blood-glands,  and  is  derived 
from  protein  tissues.  It  causes  the  formation  of  KH2P04,  with 
the  coagulation  of  myosinogen,  during  rigor  mortis. 

The  essential  nitrogenous  compounds  of  the  human  body 
are  mostly  globulins,  serum-albumin  being  the  main  exception. 
Phenol,  indol  (C8HT]ST),  and  skatol  (C8H8CH8NH)  are  formed 
by  putrefaction  of  proteins  in  the  intestines  and,  with  H2S, 
give  the  ordinary  fecal  odor  to  the  stools.  Leucin  (C5H10NH2- 
COOH)  and  tyrosin  are  normal  products  of  tryptic  digestion 
of  hemipeptons.  Like  other  amido-acids,  they  are  oxidized  in 
the  liver  into  urea,  with  production  of  heat;  when  the  liver  is 
diseased  (acute  yellow  atrophy,  P  poisoning)  they  appear  in  the 
urine. 

Urea  [(NH2)2CO]  is  the  chief  end-product  of  nitrogenous 
metabolism  in  mammals,  and  is  formed,  perhaps,  in  all  tissues 
where  proteid  decomposition  takes  place.  Its  principal  site  of 
origin  is  the  liver,  where  it  is  formed  by  dehydration  of  ammo- 
nium carbamate,  which  is  produced  in  the  tissues  by  the  union 
of  C02  and  NH3.  The  amount  of  urea  normally  ranges  from 
0.008  to  0.016  per  cent,  in  the  blood,  muscles,  and  viscera;  0.067 
per  cent,  in  the  kidney.  When  the  kidney  fails  to  functionate 
(uremia)  these  relative  proportions  may  be  nearly  reversed. 

Creatin,  or  methyl-guanidin  acetic  acid  (HNCNH2NCH3- 
CH2COOH),  is  a  product  of  proteid  decomposition,  especially  of 
the  muscles  (0.3  per  cent.).  It  is  excreted  in  the  urine  as 
creatinin:  creatin  less  water. 

The  purin,  or  alloxuric,  bodies  contain  both  the  radical 
(N2C)  of  urea  and  that  (N2C4)  of  alloxan: — 


370  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

/NH-CO\ 

'\NH-CO/ 

]Jypoxanthin,  or  sarcin  =  C5H4N40;  xanthin  =  C5H4- 
N402;  uric  acid  =  G5H4N403;  purin  =  C5H4N4;  adenin  = 
C5H5N5;  guanin  =  C5H5N50.  Nucleins  cleave  into  a  protein 
and  nucleic  acid,  and  the  latter  into  phosphoric  acid  and  allox- 
uric  bodies,  uric  acid  being  a  higher  oxidation  product  than 
xanthin  or  hypoxanthin.  Through  oxidation  and  hydrolysis 
uric  acid  can  be  decomposed  into  two  molecules  of  urea  and  one 
molecule  of  oxalic  acid,  and  when  administered  to  a  mammal 
it  is  changed  by  the  liver  into  urea.  Heteroxanthin  is  methyl- 
xanthin;  theobromin  of  cocoa  is  dimethyl-xanthin  and  isomeric 
with  paraxanthin;  caffein  is  trimethyl-xanthin.  The  alloxur 
bodies  are  normally  present  in  the  fluids  and  tissues  of  the 
body  and  in  urine.  The  normal  daily  amount  of  uric  acid  ex- 
creted in  the  urine  is  from  0.4  to  0.8  gm.;  of  purin  bases,  0.1325 
gm.  (quadrupled  in  leukemia).  The  quantity  of  uric  acid  and 
other  alloxur  bodies  is  increased  by  the  ingestion  of  tea,  coffee, 
cocoa,  and  nuclein-containing  foods,  such  as  young  flesh  and 
meat  extracts.  Eeduced  alkalinity  of  the  blood,  as  in  winter 
from  eating  meats  freely,  throws  uric  acid  out  of  solution,  to 
collect  in  the  more  acid  tissues  (spleen,  liver,  and  joints). 
With  the  vernal  tide  of  alkalinity  (due  to  freer  sweating,  with 
excretion  of  fatty  acids)  these  deposits  are  swept  out  in  the 
blood-current,  irritating  the  nerves  and  giving  rise  to  "that 
tired  feeling." 

Experiment. — Prove  futility  of  lithium  compounds  in  uric-acid  con- 
ditions by  treating  solution  of  Na2HP04  (same  salt  in  blood)  with  a 
little  Li3C6H5O7  solution.  Warm  slightly  and  note  white  ppt.  of  Li2HP04. 

Cholin  and  neurin  are  amins  of  olefins  produced  in  the 
intestines  from  proteins  by  the  action  of  bacteria.  Glycocoll, 
CH2NH2COOH,  is  a  normal  decomposition  product  from  pro- 
teins, and  is  easily  manufactured  from  gelatin.  It  exists  in  the 
bile  as  glycocholic  acid,  and  in  the  urine  with  benzoic  acid  as 
hippuric  acid  (formed  in  kidneys)  after  taking  benzoic  acid  or 
its  derivatives. 

Taurin  (NH2C2H4S03H)  is  found  in  the  spleen,  muscles, 
suprarenal  capsule,  and  in  bile  as  sodium  taurocholate.  Fellic 
acid  (C23H3804),  cholic  acid  (C24H4005),  and  choleic  acid  (C24- 
H4002)  are  probably  derived  from  the  non-nitrogenous  moiety 
of  proteids.  By  synthesis  with  taurin  and  glycocoll  in  the  liver 
they  form  taurocholic  and  glycocholic  (C26H43]Sr06)  acids,  the 
salts  of  which  are  known  as  the  bile-salts  and  have  the  function 


BONES.  371 

of  dissolving  the  more  insoluble  fatty  acids  and  soaps  produced 
by  steapsin. 

The  two  bile-acids  always  occur  as  Na  salts  in  bile  and  are 
probably  oxidation  products  of  proteins.  These  conjugated 
acids  give  rise  on  decomposition  to  cholalic  or  other  allied  acid 
and  an  amido-acid  (amido-acetic  =  glycocoll,  or  amido-ethyl- 
sulphonic  =  taurin).  Cholalic  acid  oxidizes  into  one  ketone 
and  two  aldehyd  groups,  which  have  a  reducing  power  on  hemo- 
globin; hence  the  injurious  effect  upon  the  corpuscles  of  cho- 
lemia, 

Cholesterin  (C27H45OH)  is  probably  an  accumulation  prod- 
uct of  the  hydrolysis  of  carbohydrates.  When  more  is  made 
than  can  be  utilized,  it  constitutes  waste-material  and  forms 
gall-stones. 

Bilirubin  (C16H18N203)  is  the  ordinary  coloring  matter  of 
human  bile.  Various  oxidation  products  are  biliverdin  (green), 
bilicyanin  (blue),  and  bilixanthin  (brown-yellow). 

The  final  products  of  body  decomposition  after  death  are 
such  simple  substances  as  C02,  H20,  NH3,  H2S,  and  mineral 
chlorids,  sulphates,  and  phosphates.  There  are  a  large  number 
of  intermediate  products,  the  most  important  being  the  cadav- 
eric alkaloids  or  ptomains.  The  soap-like  conversion  into  adi- 
pocere,  which  dead  bodies  sometimes  undergo,  is  due  to  the 
formation  of  Ca  salts  of  palmitic  and  stearic  acids,  through  the 
agency  of  bacteria. 

The  moving  cells  and  the  fixed  tissues  of  the  body  are  com- 
posed of  protoplasm:  that  is,  of  proteids  with  such  a  molecular 
arrangement  as  admits  of  the  phenomena  of  life. 


BONES. 

Adult  bone  contains  69  per  cent,  of  earthy  matter,  of 
which  Ca3(P04)2  constitutes  59  per  cent.  (.3  molecules  to  1  of 
carbonate);  CaC03,  7  per  cent.;  Mg3(P04)2,  1.3  per  cent.;  and 
CaF2  and  soluble  salts,  1.5  per  cent.  The  bones  of  infants  and 
young  children  contain  much  less  mineral  matter;  hence  are 
less  brittle.  The  compact  portions  of  bone  contain  more  min- 
eral matter  than  the  cancellous.  Undried  bone  is  about  half 
water. 

The  animal  matter  of  bones,  termed  ossein  (12  per  cent, 
of  undried  bone:  a  mixture  of  collagen  and  elastin)  is  closely 
combined  with  the  inorganic  salts,  so  that  the  shape  and  size 
of  a  bone  are  retained  after  these  salts  have  been  removed  with 
acids.  There  is  also  15  per  cent,  of  fat,  chiefly  in  the  marrow. 


372  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

Experiment. — Place  a  rather  long  and  narrow  bone  in  10-per-cent. 
HN03.  Remove  the  bone  in  a  day  or  two  and  tie  it  in  a  knot. 

Experiment. — Prove  presence  of  phosphates  in  acid  solution  with 
(NH4)2Mo04. 

Experiment. — Test  another  portion  of  same  solution  for  Ca  and  Mg 
as  follows :  First  treat  with  Fe2Cl6,  added  little  by  little,  testing  after  each 
addition  with  NH4HO  until  this  gives  a  ppt.  which  is  no  longer  white, 
but  yellowish;  then  add  Na2C03  until  nearly  neutral;  and  finally  ppt. 
the  ferric  phosphate  with  1  or  2  gm.  of  BaCO3;  warm  and  filter,  and  ppt. 
Ba  from  hot  filtrate  with  dilute  H2S04.  Test  the  second  filtrate  for  Ca 
by  rendering  alkaline  with  NH4OH  and  adding  excess  of  (NH4)2C204. 
Test  the  third  filtrate  for  Mg  with  Na2HPO4. 

Experiment. — Heat  some  fragments  of  bone  in  a  dry  test-tube; 
note  that  H2O  and  NH3  are  evolved,  and  then  bone-oil  and  inflammable 
gases,  leaving  bone-black  and  bone-ash.  Take  up  a  little  of  the  black 
mass  on  a  Pt  loop,  burn  away  C,  and  test  for  carbonate  with  an  acid. 

In  old  age  the  bones  become  more  porous;  hence  more 
fragile.  In  most  bone  diseases  (rickets,  osteomalacia,  and  osteo- 
porosis) the  lime-salts  are  diminished,  while  the  organic  con- 
stituents undergo  qualitative  changes.  The  phosphates  are 
permanently  reduced  in  the  urine  after  castration  of  man  or 
woman,  thereby  benefiting  osteomalacia. 


TEETH. 

The  composition  of  teeth  is  much  like  that  of  bone,  dentine 
containing  28  parts  of  animal  matter  and  72  parts  of  mineral, 
with  5  or  6  per  cent,  of  water.  Cement,  or  crusta  petrosa,  is 
true  bone.  Enamel  is  the  hardest  tissue  in  the  body,  containing 
only  3  */2  Per  cent,  of  organic  matter,  and  composed  chiefly 
(90  per  cent.)  of  calcium  phosphate  and  fluorid.  The  enamel 
of  young  infants  contains  from  77  to  84  per  cent,  of  mineral 
matter. 

Experiment. — Estimate  the  water  in  a  freshly  extracted  tooth: 
Weigh  out  a  gram  of  the  crushed  tooth  in  a  tared  porcelain  crucible,  and 
place  in  the  air-bath  at  95°  for  an  hour.  Remove,  cool,  and  weigh,  and 
return  to  the  oven  for  another  half-hour;  then  cool  and  weigh  again.  If 
the  last  two  weights  correspond,  the  tooth  is  dehydrated;  otherwise  it 
should  be  again  heated  until  the  weight  is  constant. 

Experiment  to  Estimate  Organic  and  Inorganic  Matter. — Place 
the  dehydrated  product  of  the  preceding  experiment  on  a  triangle,  cover 
the  crucible,  and  burn  the  organic  matter;  then  remove,  cover,  and 
calcine  at  a  red  heat  till  the  ash  is  nearly  white.  Cool  and  weigh. 

Experiment. — Place  a  tooth  in  10-per-cent.  HNO3  for  two  or  three 
days.  Then  pour  off  the  acid  mineral  solution  and  test  it  for  phosphates 
with  (NH4)2MoO4;  and  boil  the  organic  residue  with  water,  forming  a 
gelatin-jelly  on  cooling. 

Acid  substances,  Hg,  As,  alum,  and  H202  are  especially 
injurious  to  the  teeth.  Liquid  medicines  containing  acids,  like 


MUSCLE.  373 

tincture  of  iron,  should  be  taken  well  diluted  through  a  glass 
tube.  Eating  much  candy  injures  the  teeth  by  reason  of  the 
lactic  acid  produced  by  fermentation. 

The  common  brown  variety  of  dental  caries  is  said  to  be 
due  to  nascent  HC1;  the  white  or  rapid  variety  to  ETN~03, 
formed  by  combination  of  NH3  and  nascent  0  evolved  during 
fermentation;  the  black  variety  may  be  caused  by  H2S04, 
formed  by  the  nascent  0  and  H2S  of  putrefaction.  Acids  act 
more  readily  on  dentine  than  enamel;  hence  the  tendency  of  a 
cavity  to  enlarge  centrally.  These  acids  are  formed  by  the 
action  on  foods  of  various  fungi  and  bacteria.  Local  inflam- 
mations, mental  strain,  pregnancy,  and  lactation  predispose  to 
caries. 

The  tartar  of  teeth  is  a  gray,  brown,  or  yellow  deposit  from 
alkaline  saliva,  and  consists  chiefly  of  Ca3(P04)2,  with  a  little 
CaC03  and  more  or  less  organic  matter,  molds  and  bacteria, 
silica,  and  alkaline  salts.  The  salivary  secretions  hold  lime- 
salts  in  solution  by  the  aid  of  C02.  On  passing  into  the  mouth 
this  is  neutralized  by  NU3  and  other  alkalies  of  putrefactive 
origin,  and  the  lime  salts  are  precipitated  as  tartar. 

MUSCLE. 

Muscular  tissue  is  made  up  mostly  of  collagen  and  myo- 
sinogen.  Muscle-plasma  contains  myoalbumin,  myoglobulin, 
myoalbumose,  hemoglobin,  myohematin,  pepsin,  rnyosin  fer- 
ment, and  amylolytic  ferments;  sarcolactic,  formic,  and  acetic 
acids;  glycogen,  maltose,  glucose,  and  inosit;  various  salts, 
especially  the  phosphates  of  Mg,  Ca,  and  K  and  KC1;  and  the 
extractives,  as  urea,  creatin,  guanin,  xanthin,  hypoxanthin,  and 
uric  acid.  These  occur  free  and  in  nucleins.  The  sarcolemma 
is  composed  of  an  albuminoid  resembling  elastin.  C02  is  the 
principal  gas  present  in  muscles.  Half  the  proteid  of  the  body 
and  half  the  water  are  in  the  muscles. 

The  reaction  of  resting  muscle  is  alkaline;  during  con- 
tractions it  becomes  acid,  from  sarcolactic  acid  evolved  by  the 
breaking  down  of  proteids.  Muscle  is  three-fourths  water,  and 
its  density  is  about  1.055:  nearly  that  of  the  blood. 

Rigor  mortis  is  due  to  coagulation  of  myosinogen  and  para- 
myosinogen  by  fibrin  ferment,  forming  a  clot  of  myosin.  Sar- 
colactic acid  and  acid  potassium  phosphate  are  also  generated 
in  considerable  quantity  after  death,  and  probably  aid  in  the 
process  of  coagulation.  Muscular  fatigue  has  been  ascribed  to 
the  irritating  effects  on  the  nerve-plates  of  an  excess  of  sarco- 
lactic acid  and  extractives. 


374  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 


NERVE-SUBSTANCE. 

The  composition  of  brain  and  nerves  differs  from  that  of 
other  organs  in  containing  a  large  proportion  of  phosphorized 
fatty  compounds,  such  as  cerebrin,  protagon,  lecithin,  and  choles- 
terin;  the  white  substance  is  more  fatty  than  the  gray.  It  is 
claimed  that  the  anesthetic  effect  of  ether  and  chloroform  is 
due  to  their  solvent  action  upon  the  fat  of  the  neurons.  KC1 
and  the  phosphates  are  the  chief  salts.  The  neurolemma  con- 
sists mainly  of  neurokeratin.  The  amount  of  water  normally 
in  the  brain  is  from  71  to  83  per  cent.;  in  the  nerves,  72  per 
cent.  The  chief  decomposition  products  are  neurin,  cholin, 
fatty  acids,  glycerophosphoric  acid,  and  the  purin  bodies.  These 
products  are  found  in  excess  in  the  blood  in  organic  nervous  dis- 
eases. 


EPIDERMAL  STRUCTURES. 

Epithelia,  nails,  and  hair  are  composed  chiefly  of  keratins. 
Human  hair  contains  4  or  5  per  cent,  of  S. 

Experiment. — Boil  some  hairs  or  nail-parings  with  a  little  KHO. 
Then  add  HC1  and  note  odor  of  H2S. 

The  nails  contain  considerable  K3P04.  The  granular  pig- 
ment melanin  is  present  in  hair,  the  rete  mucosum,  and  the 
pigment-layers  of  the  retina,  choroid,  and  iris.  It  is  derived 
from  blood-pigment.  Melanotic  tumors  contain  a  considerable 
amount  of  this  pigment.  The  loss  of  pigment  makes  hair  gray, 
and  its  absence  from  the  iris  is  noticed  in  albinos.  The  en- 
trance of  air  into  the  shafts  of  hair,  as  in  grief  or  fright,  turns 
the  hair  white,  but  the  color  may  sometimes  be  restored  by 
driving  out  the  air  with  hot  water. 

The  dermatitis  that  follows  contact  with  the  poison-ivy 
and  other  plants  of  the  rhus  group  is  attributed  to  irritation 
by  the  volatile  principle,  toxicodendric  acid;  hence  the  efficacy 
of  alkaline  baths. 


CONNECTIVE  TISSUES. 

White,  fibrous  tissue  consists  of  collagen;  elastic  tissue, 
of  elastin.  The  cement  substance  is  a  form  of  muciri.  Fetal 
fibers  yield  mucin  in  place  of  gelatin  after  being  boiled  with 
water. 


THE  BLOOD.  375 


CARTILAGE. 

The  matrix,  capsules,  and  cancellous  substance  are  com- 
posed of  collagen  or  chondrin;  the  cells,  of  a  globulin.  Cor- 
neal  tissue  also  yields  a  chondrin  on  boiling.  Chondrigen  itself, 
the  organic  basis  of  cartilage,  is  a  mixture  of  collagen;  an 
elastin-like  substance;  chondromucoid;  and  chondroitic  acid, 


THE  VISCERA. 

These  consist,  on  the  average,  of  about  three-fourths  water, 
and  are  alkaline  in  reaction,  but  become  acid  after  death.  Pig- 
ment accumulates  in  the  liver  in  malaria,  from  the  destruction 
of  red  corpuscles.  The  spleen-pulp  contains  considerable  com- 
bined iron.  The  thyroid  gland  is  distinguished  for  its  thy- 
roidin  and  glairy,  colloid  secretion.  Calcareous  concretions 
have  been  found  in  all  the  viscera,  and  especially  in  pulmonary 
tubercles. 

Visceral  degenerations  include  fatty,  amyloid,  mucoid,  col- 
loid, calcareous,  and  pigmentary.  The  change  to  fat  occurs 
when  oxidation  of  proteids  is  deficient,  as  in  P,  As,  and  Sb 
poisoning;  alcoholism;  and  yellow  atrophy.  Amyloid  is  a  pale, 
waxy,  pathologic  protein  formed  in  the  course  of  chronic  wast- 
ing diseases.  Mucoid  degeneration  is  manifested  by  excess  of 
mucin.  Vitreous  colloid  has  the  formula  C16H15N06;  it  con- 
sists of  ISTaCl  and  colloidin,  which  is  colored  red  by  Millon's 
reagent.  The  melanin  of  pigmentary  degeneration  (Addison's 
disease,  melanotic  cancer)  is  identic  with  normal  melanin,  and 
is  probably  derived  from  hemoglobin.  In  atheroma  of  the 
blood-vessels  the  yellow  spots  show  fatty  and  calcareous  degen- 
eration. 

THE  BLOOD. 

This  vital  fluid  constitutes  about  V20  part,  by  weight,  of 
the  human  body.  It  is  795  parts  water  per  1000,  and  has  nor- 
mally a  sp.  gr.  of  1.055  to  1.062;  higher  in  men  than  in  women, 
and  reduced  proportionately  with  hemoglobin  reduction. 

Experiment. — Determine  sp.  gr.  of  blood  by  making  a  mixture  of 
benzol  with  chloroform  in  such  proportions  as  to  be  somewhat  lighter 
than  blood.  Let  a  drop  of  blood  from  the  end  of  the  finger  fall  into  the 
liquid,  and  when  it  has  sunk  add  chloroform  drop  by  drop,  with  stirring, 
until  the  drop  of  blood  floats  midway  in  the  liquid.  Then  filter  out  the 
blood  and  find  sp.  gr.  of  mixture  with  hydrometer. 

Blood  is  saline  because  of  alkaline  chlorids,  which  keep 


376  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

the  globulins  in  solution,  prevent  disintegration  of  the  cor- 
puscles, and  aid  osmosis.  The  alkalinity  necessary  for  proper 
oxidation  is  maintained  by  Na2HP04  and  especially  Na2C03, 
which  is  associated  with  serum-albumin,  the  combination  being 
dissociated  by  C02  with  formation  of  NaHC03. 

Experiment. — Prove  alkalinity  of  blood  by  placing  a  drop  of  red 
litmus  solution  on  a  porous  porcelain  plate.  When  dry  leave  a  drop  of 
blood  on  the  spot  for  a  minute,  then  wash  off  with  water. 

The  alkalinity  of  the  blood  can  be  estimated  by  mixing 
5  c.c.  of  fresh  blood  with  45  or  50  c.c.  of  0.25  per  cent.  (NH4)2- 
C204  solution  (prevents  coagulation),  titrating  the  mixture  with 
N/25  H2C4H406  solution,  using  as  an  indicator  lacmoid  paper 
soaked  in  concentrated  MgS04  solution. 

The  normal  alkalinity  is  decreased  by  the  production  of 
sulphuric,  phosphoric,  and  the  volatile  fatty  acids  in  the  rapid 
protein  catabolism  of  fevers,  cancer,  and  diabetes. 

The  opacity  of  blood  is  due  to  the  suspended  blood-corpus- 
cles, the  red  variety  of  which  gives  color  mainly  to  the  blood, 
though  serum  also  contains  a  coloring  matter  termed  lutein. 

Experiment. — Gently  shake  some  fresh  blood  (diluted  1  to  5)  in  a 
test-tube  with  ether.  The  cells  are  dissolved,  and  the  liquid  becomes 
transparent  or  laky. 

The  number  of  leucocytes  is  increased  (leucocytosis)  in 
leukemia  and  in  most  inflammations,  particularly  when  ending 
in  suppuration.  The  erythrocytes  are  diminished  in  anemias 
(with  proportionate  oligochromemia  in  simple  secondary — in 
excess  of  oligochromemia  in  pernicious).  In  chlorosis  there  is 
great  hemoglobin  reduction  with  but  slight  lessening  of  cor- 
puscles. 

Hydremia  is  particularly  noticeable  after  hemorrhages, 
and  is  accompanied  by  absolute  hypalbuminosis.  Increase  of 
fibrin  (hyperinosis)  has  been  noted  in  pneumonia,  erysipelas, 
and  acute  rheumatism.  The  opposite  condition,  hypinosis,  is 
said  to  occur  in  malaria,  pyemia,  and  pernicious  anemia.  In 
general,  the  percentage  of  proteids  varies  inversely  with  the 
amount  of  water  in  the  blood. 

The  sugar  in  the  blood  is  increased  up  to  9  per  mille  in 
diabetes,  and  is  also  considerably  increased  in  carcinoma.  It 
may  be  estimated  in  the  usual  way  after  removing  the  proteins 
by  boiling  with  Na2S04.  Acetone  is  found  in  the  blood  in 
fevers  and  diabetes.  The  glycogen  reaction  is  pronounced  in 
diabetes  and  leukemia.  To  test  for  glycogen  a  drop  of  blood 
is  spread  between  cover-slips  and  allowed  to  dry,  then  treated 
with  a  solution  containing  1  gm.  I  and  3  gm.  KI  in  100  gm. 


THE  BLOOD. 


377 


of  concentrated  mucilage.  The  glycogen  appears  as  brown 
granules  free  or  in  the  leucocytes.  Cellulose  has  been  found 
in  the  blood  in  tuberculosis. 

The  composition  of  the  blood  may  be  represented  some- 
what graphically  by  the  following  outline: — 


Plasma 

(60  per  cent. 

or  less ) 


Blood 


Serum 


Gases  1 


Corpuscles 

( 40  per  cent 

or  more) 


Water  (90  per  cent.). 
Serum-albumin  (4.5  per  cent.). 
Serum-globulin  (3.1  per  cent.). 
Dextrose  (0.1  to  0.15  per  cent. ). 
Salts  =  NaCl  (0.65  percent. ),  CaCl2,  KC1, 

phosphates,  sulphates,  carbonates. 
Fat  (0.1  to  1.2  per  cent.). 
Ferments :    diastatic,    glycolytic,    steato- 

lytic. 

Extractives  =  urea  (0.016  per  cent. ),  uric 
acid,  creatin,  sarcolactic  acid,  etc. 

O  =  20  volumes  per  cent,  in  ar- 
terial, 12  per  cent  in  venous. 
CO2  =  39  volumes  per  cent,  in 
arterial,  46  per  cent,  in   ve- 
nous. 
N  =  1  or  2  volumes  per  cent,  in 

arterial  and  venous. 
Fibrinogen  (0.5  per  cent.). 
Stroma. 
Hemoglobin  (about  90  per  cent,  of  dry 

corpuscle). 
Lecithin. 
Cholesterin. 

Salts  =  KC1  and  K2HPO4. 
Nucleo-histon. 
Lecithin. 
Cholesterin. 
Fatty  granules. 
Albumose. 
K,HPO4. 
^  Blood-plates  =  nuclein. 


White 

(1  to  350 

of  red) 


An  increase  of  fat  (lipemia)  is  noted  after  the  ingestion  of 
large  amounts  of  fatty  foods  and  in  obesity,  chronic  alcoholism, 
hepatic  disease,  and  after  injury  to  the  long  bones.  Lipacidemia 
has  been  observed  in  fevers,  leukemia,  and  diabetes. 

Cholemia  is  met  with  in  cases  of  obstinate  jaundice,  ex- 
cessive secretion  of  bile,  and  destruction  of  red  blood-corpus- 
cles. 

Other  pathologic  extractives  occasionally  encountered  are 
xanthin,  hypoxanthin,  paraxanthin,  guanin,  adenin,  leucin, 
tyrosin,  lactic  acid,  and  beta-oxybutyric  acid. 

The  coagulation  of  blood  is  believed  to  be  due  first  to  the 
union  of  Ca  salts  (CaCl2  especially)  with  the  zymogen  pro- 


378  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

thrombin  (from  leucocytes  of  shed  blood),  forming  fibrin-fer- 
ment. This,  in  turn,  combines  with  fibrinogen  to  form  a  net- 
work of  fibrin-threads,  which  enmesh  and  contract  upon  the 
corpuscles,  making  the  clot  and  setting  free  the  serum.  The 
so-called  buffy  coat  is  made  up  of  leucocytes.  Freshly  drawn 
blood  is  readily  defibrinated  by  whipping  quickly  with  a  stick 
or  a  fork.  The  elastic  strings  of  fibrin  thus  collected  when 
thoroughly  washed  resemble  boiled  white  of  egg.  For  the  tests 
given  below  defibrinated  blood  should  be  employed. 

To  separate  blood-serum  from  the  clot  the  blood  should 
be  received  in  a  rather  wide  vessel,  and  as  soon  as  it  clots  be 
placed  in  an  ice-chest  for  thirty-six  to  forty-eight  hours  or 
longer,  until  the  serum  is  clear  and  straw-colored.  The  cor- 
puscles can  be  pptd.  from  defibrinated  blood  by  adding  a  1/10 
saturated  aqueous  solution  of  NaCl  to  yio  its  volume  of  the 
blood,  pouring  the  mixture  into  a  shallow  dish,  and  after  set- 
tling decanting. 

The  most  important  constituent  of  the  blood  is  the  color- 
ing matter  hemoglobin,  which  constitutes  over  90  per  cent,  of 
the  organic  matter  of  the  red  corpuscles,  and  in  the  dry  state 
contains  0.42  per  cent,  of  Fe.  It  carries  0  (molecule  for  mole- 
cule) from  the  lungs  to  the  tissues,  in  a  loose  combination 
known  as  oxyhemoglobin.  Hemoglobin,  or  reduced  hemo- 
globin, is  the  coloring  matter  of  venous  blood,  and  oxyhemo- 
globin that  of  arterial  blood.  Hemoglobin  crystallizes  with 
difficulty  in  purple  crystals;  oxyhemoglobin  more  readily  in 
long,  bright-reddish  prisms.  H20  and  some  other  reagents 
remove  the  coloring  matter  from  the  corpuscles  and  thus  render 
blood  darker,  whereas  salt  solutions  have  the  opposite  effect. 
On  long  exposure  to  air  oxyhemoglobin  stains  isomerize  into 
the  more  stable  brown  acid  methemoglobin,  which  is  found 
also  at  times  in  cystic  fluids  and  transudations.  Oxidizing 
agents,  such  as  H202,  likewise  convert  oxyhemoglobin  into 
methemoglobin.  The  latter  crystallizes  in  red-brown  needles 
or  plates,  and  yields  a  brown,  aqueous  solution,  turning  red 
on  rendering  alkaline. 

On  heating  with  acids  or  alkalies  oxyhemoglobin  decom- 
poses into  globulin  and  the  Fe  pigment  hematin;  reduced  hemo- 
globin into  hemochrom  and  a  globulin.  Hematin  is  dark  brown 
or  blue-black,  and  amorphous.  The  dark  color  of  "coffee- 
ground"  vomit  in  gastric  cancer  is  due  to  hematin,  formed  by 
the  action  of  HC1  on  blood.  Hematin  combines  with  nascent 
HC1  to  form  hematin  hydrochlorate,  or  hemin:  a  crystalline 
substance  of  vital  importance  in  the  identification  of  blood- 
stains. 


THE  BLOOD.  379 

Experiment  to  Identify  a  Blood-stain  on  a  Piece  of  Cloth  or  Wood. 
— Add  to  a  few  of  the  fibers  or  scrapings  on  a  glass  slide  a  drop  of 
1-per-cent.  NaCl  solution,  and  warm  very  gently  till  nearly  dry.  Then 
add  at  once  a  drop  or  two  of  glacial  acetic  acid,  put  on  a  cover-glass, 
and  warm  again  gently  till  nearly  dry.  Allow  to  cool  and  examine  under 
microscope  for  small,  dark-red,  rhombic,  hemin  crystals.  These  Teich- 
mann  crystals  are  insoluble  in  water,  but  dissolve  in  alkalies,  with  for- 
mation of  hematin. 

Hematoporphyrin  is  an  iron-free  derivative  of  hematin, 
prepared  by  the  action  of  strong  acids,  and  isomeric  with  bili- 
rubin.  It  is  wine-red  in  color,  and  may  be  noted  in  the  gastro- 
intestinal contents  after  mineral-acid  poisoning. 

Experiment. — To  10  c.c.  of  H2S04  in  a  test-tube  add  4  or  5  drops  of 
blood,  shaking  thoroughly  with  each  addition.  Note  the  color  of  hema- 
toporphyrin. 


Fig.  47.— Hemin  Crystals. 

Hematoidin  is  a  hemoglobin  derivative  similar  to,  if  not 
identic  with,  bilirubin.  It  appears  in  orange-  or  ruby-  colored, 
amorphous  particles  in  old  extravasations  and  in  the  sputum, 
urine,  and  feces  after  hemorrhages. 

CO  hemoglobin  is  a  compound  similar  to  oxyhemoglobin, 
but  is  more  stable;  hence  the  grave  character  of  CO  poisoning, 
since  0  cannot  displace  CO  and  be  carried  to  the  tissues. 

Experiment. — Pass  a  current  of  illuminating  gas  for  a  few  minutes 
through  some  diluted  blood  (1  to  50).  Note  change  of  color  to  cherry 
red.  Prove  that  CO  hemoglobin  is  a  stronger  combination  than  oxy- 
hemoglobin by  treating  dilute  solutions  of  each  with  twice  as  much 
strong  NaHO  solution  (pure  blood  becomes  brownish,  with  a  green 
tinge) ;  with  H2S  (pure  blood  turns  green) ;  and  with  a  drop  each  of 
dilute  HC2H3O2  and  K4FeCy8  solution  (brownish  ppt.  with  pure  blood), 
in  all  of  which  tests  the  CO  hemoglobin  solution  remains  unchanged  in 
color. 


380  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

The  spectroscope  furnishes  the  most  delicate  evidence  of 
the  presence  of  blood  in  solution,  readily  showing  1  part  in 
10,000. 

Spectroscopic  Tests. — Dilute  defibrinated  blood  with  50  parts  of 
water,  and  suspend  some  of  the  fluid  in  a  narrow  test-tube  about  an 
inch  before  the  slit  of  the  instrument,  with  a  fish-tail  burner  two  inches 
farther  away.  1.  Compare  the  position  of  the  oxyhemoglobin  with  that 
of  the  Na  lines.  2.  Reduce  the  oxyhemoglobin  by  adding  a  drop  or  two 
of  Stokes's  solution  (2  FeSO4  and  3  H2C4H4O6  dissolved  in  H20  and  ren- 
dered alkaline  with  NH4HO),  and  note  position  of  single  band.  Shaking 
restores  the  two  characteristic  oxyhemoglobin  bands.  3.  To  the  reduced 
hemoglobin  add  a  few  drops  of  strong  NaHO  solution,  forming  hemo- 
chromogen,  and  compare  two  bands  with  those  of  oxyhemoglobin.  4. 
Tests  can  be  made  with  less  dilute  blood  (1  to  15  or  1  to  20)  for  the 
spectra  of  methemoglobin  (warm  dilute  blood  with  a  few  crystals  of 
KC10J,  alkaline  hematin  (heat  blood  with  NaHO  till  color  becomes  a 
greenish  brown),  CO  hemoglobin  (blood  diluted  1  to  50),  and  hemato- 
porphyrin. 

It  is  possible  that  hemoglobin,  like  chlorophyl,  acts  as  a 
dehydrating  agent,  forming  glycogen  from  glucose.  Blood 
leaving  a  resting  gland  is  dark  and  venous;  that  from  an  active 
gland  is  brighter,  owing  to  C02  being  given  off  in  the  secretion. 

Plumage  pigments  consist  of  lipochromoids  and  melanoids 
closely  related  to  the  pigments  of  fishes  and  reptiles.  The 
blood  of  most  insects  is  green  (from  chlorophyl)  and  darkens 
on  exposure  to  the  air. 


SECRETIONS. 

These  are  the  special  products  of  particular  glands.  They 
are  mostly  liquid  or  semiliquid,  and  are  composed  of  water, 
inorganic  salts,  and  organic  compounds.  True  secretions  are 
formed  from  the  blood,  but  do  not  pre-exist  in  the  blood,  and 
are  of  service  to  the  organism.  As  the  blood  is  alkaline,  so 
all  the  secretions  (except  gastric  juice  and  bile)  are  alkaline 
and  of  lower  sp.  gr.  than  the  blood.  Psychic  emotions  affect 
both  the  quantity  and  quality  of  secretions,  and  they  are  gen- 
erally diminished  in  fevers. 

The  digestive  fluids  constitute  the  most  important  class 
of  secretions.  They  all  have  a  somewhat  similar  composition 
(phosphates,  chlorids,  carbonates,  sulphates  of  Na,  K,  Ca,  and 
Mg)  except  in  regard  to  the  ferments  which  they  contain. 
These  exist  in  the  glands  as  zymogens,  needing  to  combine  with 
dilute  acids  or  alkalies  to  form  the  full  enzyme.  The  following 
table  shows  the  chief  points  in  the  chemistry  of  these  secre- 
tions:— 


B  C 


PLATE  IV 

D  Eb 


ABSORPTION-SPECTRA. 

(Rockwood.) 


Oxyhemoglobin. 

Hemoglobin. 

CO  hemoglobin  and  CO  hemochromogen. 

Methemoglobin,  alkaline. 

Hematoporphyrin,  acid. 


6.  Hematoporphyrin,  alkaline. 


7.  Hemochromogen,  alkaline. 

8.  Hematin,  acid. 

Q.  Hematin,  alkaline. 

10.  Sulphur  methemoglobin. 

11.  Methemoglobin,  neutral  or  faintly  acid. 

12.  Pettenkofer's  test  for  biliary  acids. 


SECRETIONS. 


381 


SECRETION. 

AVERAGE 
DAILY 
QUANTITY. 

SPECIFIC 
GRAVITY. 

FERMENTS. 

OTHER  CONSTITUENTS. 

Saliva. 

800  to 
1500  c.c. 

1.004  to 
1.008 

Ptyalin  (0.1  per  cent.), 
amylolytic  (on  boiled 
starch). 

Mucin  (1.4  per  cent.). 

Potassium  sulphocyanate 
(0.1  per  cent.). 

Epithelia  and  salivary  cor- 
puscles. 

Inorganic  salts  (2  p.  m.)  = 
chjorids,    carbonates,    ni- 
trites,    sulphates,      phos- 
phates of  Na,  K,  Ca,  and 
Mg. 

Gastric 
juice. 

5000  to 
10,000  c.c. 

1.002  to 
1.003 

Pepsin  (1.75  per  cent.), 
proteolytic. 

Hydrochloric  acid  (free,  0.2 
per  cent.). 

Rennin,  milk-curd  li  n  g 
ferment. 

Organic  acids  =  lactic,    ace- 
tic, butyric. 

A  glycolytic  ferment. 

Acid  phosphates    (0.02    per 
cent.  )  of  Mg,  Ca,  and  Fe. 

Pseudopepsin. 

Alkaline  chlorids    (0.2    per 
cent.). 

Pancreatic 
juice. 

200  c.c. 

1.010  to 
1.015 

Trypsin,  proteolytic. 

Sodium  carbonate   (0.3  per 
cent.). 

Amylopsin,    amylolytic. 

Fats  and  soap. 

Steapsin,  fat-cleaving. 

Albumin. 

Rennin,    milk-curdling. 

Leucin  and  tyrosin. 

Bile. 

500  to 
800c.c. 

1.020 

Pialyn,   fat-cleaving. 

Bile-salts  (7.5  per  cent.)  and 
pigments. 

Fat  (0.9  per  cent.  )  and  soap. 

Cholesterin  (0.25  per  cent.), 
lecithin,  and  urea. 

Mucus  and  albumin. 

Sodium  carbonate    (0.25   to 
0.5  per  cent.). 

Salts  of  Ca,  Mg,  Fe,  and  Cu. 

Intestinal 
juice. 

Unknown 

1.011 

Invertase,  glycolytic. 
Maltase,  glycolytic. 

Salts. 

Erepsin,  proteolytic. 

382  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

SALIVA. 

Normal  saliva  is  opalescent,  odorless,  frothy,  slightly 
cloudy,  and  faintly  alkaline.  The  quantity  of  saliva  is  dimin- 
ished by  atropin,  in  fevers,  diabetes,  nephritis,  and  severe  diar- 
rheas; increased  (salivation,  ptyalism)  by  Hg,  KI,  pilocarpin, 
acids,  and  by  mastication,  pregnancy,  and  local  inflammatory 
conditions.  It  has  a  bad  smell  in  scurvy,  gingivitis,  and  mer- 
curial salivation.  It  is  acid  in  the  morning  before  breakfast 
and  sometimes  after  much  talking,  and  may  be  constantly  acid 
from  oral  fermentation  (lactic  acid),  Hg  salivation,  and  in  rheu- 
matism and  diabetes.  When  it  is  strongly  acid,  considerable 
galvanic  action  may  take  place  with  dental  fillings  or  metal 
plates.  Albumin  is  present  in  ptyalism;  urea,  in  nephritis. 
The  secretion  of  the  parotid  gland  is  most  fluid;  that  of  the 
sublingual  and  submaxillary  more  slimy.  There  is  only  a  trace 
of  ptyalin  in  saliva  for  some  months  after  birth. 

Experiment. — Test  for  mucin  by  adding  to  clear  saliva  acetic  acid 
drop  by  drop,  and  note  ppt.  of  mucin  in  white  strings  or  flakes. 

Experiment. — Test  for  sulphocyanate  in  saliva  by  filtering  a  small 
quantity  and  adding  a  drop  of  very  dilute  Fe2Cl0.  The  red  color  disap- 
pears on  adding  HgCl2.  This  test  is  sometimes  negative. 

Salivary  calculi  depend  on  inflammatory  conditions,  and 
are  sometimes  deposited  in  the  salivary  ducts.  They  are  com- 
posed of  CaC03  and  Ca3(P04)2  (cemented  with  organic  matter), 
which  salts  are  normally  held  in  solution  by  C02. 

Test  for  Hg  in  Saliva. — Collect  100  c.c.  or  more  of  saliva,  acidulate 
with  HC1,  digest  on  water -bath  for  two  hours,  adding  now  and  then  a 
drop  of  HN03.  Filter  and  concentrate  to  10  c.c.  Take  a  little  of  this 
in  a  test-tube,  add  a  small  fragment  of  bright  Cu,  and  boil.  If  Hg  is 
present,  it  will  form  a  gray  coating  on  the  Cu,  driven  off  by  heating. 

GASTRIC  JUICE. 

This  is  a  thin,  pale-yellow  liquid  containing  0.5  per  cent, 
of  solids.  It  is  often  mixed,  however,  as  usually  obtained,  with 
viscid  mucus  from  the  throat.  The  normally  frankly-acid  re- 
action of  gastric  juice  is  due  chiefly  to  the  free  HC1,  partly  to 
the  acid  phosphates.  The  HC1  is  derived  from  common  salt 
by  the  mass  action  of  C02  or  by  reaction  with  the  sodium  bicar- 
bonate of  the  blood: — 

NaCl  +  NaHC03  =  Na2C03  +  HC1 

Free  HC1  averages  about  0.2  per  cent,  in  the  gastric  juice. 
The  amount  increases  from  the  beginning  of  digestion.  It  com- 
bines loosely  with  protein  molecules  and  probably  with  pepsin. 


SECRETIONS.  383 

HC1  is  deficient  (hypochlorhydria)  in  most  cases  of  ordinary 
functional  dyspepsia,  and  in  fevers  and  renal,  hepatic,  cardiac, 
and  pulmonary  diseases.  It  is  greatly  diminished  or  absent  in 
cancer  of  the  stomach  and  chronic  atrophic  gastritis.  Hyper- 
chlorhydria  is  usually  a  neurosis  (often  with  hypersecretion  = 
gastrosuccorrhea),  and  is  a  significant  sign  of  gastric  ulcer. 

Free  HC1  is  an  effective  germicide,  though  not  destructive 
to  spores.  Bacterial  fermentation,  of  carbohydrates  mostly, 
with  production  of  organic  acids  (lactic,  acetic,  and  butyric) 
and  alcohol,  is  therefore  to  be  expected  with  hypochlorhydria. 
Hyperacidity  may  be  due  either  to  excess  of  HC1  or  of  organic 
acids.  Mineral  acids  given  before  meals  decrease  the  secretion 
of  HC1;  given  after,  they  prevent  the  formation  of  organic 
acids.  Alkalies  before  meals  favor  the  secretion  of  HC1;  given 
after  meals  they  relieve  acid  eructations  from  any  cause,  but 
only  for  the  time  being. 

The  fatty  acids  and  simple  gases  (H,  C02,  and  CH4)  are 
also  found  in  the  stomach-contents  in  some  cases  of  hyper- 
chlorhydria  with  retention;  these  cases  are,  however,  not  ac- 
companied by  •  putrefactive  changes.  Frequent  feedings  also 
interfere  with  gastric  self-disinfection.  Lactic  acid  is  not  found 
normally  after  digestion  has  progressed  for  more  than  a  half- 
hour,  owing  to  the  inhibiting  action  of  HC1,  or  until  the  entire 
food  mass  has  been  permeated  by  the  mineral  acid.  The  suc- 
cus  pyloricus  is  said  to  be  alkaline,  as  is  the  reaction  of  the 
slimy  secretion  of  the  stomach  in  a  state  of  rest.  Fermentation 
is  best  prevented  by  restriction  of  carbohydrates  and  by  the 
administration  of  HC1  in  sufficient  doses  after  meals.  The 
stomach-contents  generally  contain  a  little  mucus,  which  is 
greatly  increased  in  the  acute  and  the  mucous  forms  of  sub- 
acute  and  chronic  gastritis. 

Experiment. — Make  NaH,P04  by  adding  H3PO4  gradually  to  Na2- 
HP04  solution  till  it  does  not  ppt.  BaCl2.  Show  with  litmus-paper  that 
the  acid  phosphate  thus  formed  is  not  neutralized  by  CaCO3,  whereas 
free  dilute  acids  are. 

Experiment. — Make  a  0.2-per-cent.  solution  of  HC1.  Show  that  it 
turns  methyl-violet  solution  blue,  congo-red  blue,  and  tropeolin  00  from 
yellow  to  red. 

Experiment. — Test  the  HC1  solution  in  a  casserole  by  adding  a  few 
drops  of  a  5-per-cent.  solution  each  of  cane-sugar  and  resorcin.  On  warm- 
ing gently  a  red  line  appears  at  the  border. 

Experiment. — Make  a  0.1-per-cent.  solution  of  lactic  acid;  also  dis- 
solve 0.1  c.c.  of  a  saturated  alcoholic  solution  of  gentian-violet  in  250 
c.c.  of  distilled  water,  and  5  c.c.  of  official  solution  of  Fe2Cl6  in  20  c.c. 
of  water.  Add  a  drop  of  the  iron  solution  to  a  drop  of  the  gentian-violet 
solution,  producing  a  bluish-violet  color,  which  is  turned  greenish  yellow 
by  a  few  drops  of  the  lactic  acid. 

(See  further  under  "Clinic  Chemistry.") 


384  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

BILE. 

Bile  is  a  mixture  of  hepatic  cell-secretion  and  of  mucus 
derived  from  the  gall-bladder  and  ducts,  and  is  both  a  secretion 
and  an  excretion.  It  is  thick,  viscid,  and  very  bitter,  and  varies 
in  color  from  light  yellow  to  greenish  blue.  It  contains  from 
7  to  18  per  cent,  of  solids  (1  to  4  per  cent,  from  a  fistula). 

The  chief  bile-salts  proper  are  the  glycocholate  and  tauro- 
cholate  of  sodium,  the  former  occurring  in  four  times  the  quan- 
tity of  the  latter.  They  are  dextrorotatory,  and  are  pptd.  as 
fine  needles  from  alcoholic  solutions  by  addition  of  ether.  The 
office  of  these  salts  in  digestion  is  to  ppt.  peptons  in  the  small 
intestine,  thus  aiding  their  absorption.  They  also  keep  the 
fatty  acids  and  lecithin  and  cholesterin  in  solution. 

Normal  bile  contains  two  pigments:  bilirubin,  or  bilifulvin 
(CleH18N208)  (reddish  yellow);  and  biliverdin  (C16H18N204) 
(green).  The  former  is  derived  from  hematin,  and  yields  the 
latter  by  oxidation;  on  putrefactive  reduction  hydrobilirubin 
(stercobilin,  urobilin)  results.  Biliverdin  is  insoluble  in  CHC13, 
which  dissolves  bilirubin.  Bile-pigment  contains  no  Fe,  which 
has  been  split  off  in  the  liver. 

Altered  bile  and  bile-stones  contain  other  pigments,  such 
as  bilifuscin  (brown),  biliprasin  (greenish  black),  bilicyanin 
(bluish),  and  choletelin  (yellow  to  brown).  Gall-stones  are 
composed  chiefly  of  cholesterin,  with  a  nucleus  of  calcium- 
bilirubin.  Cholesterin  calculi  are  whitish  and  greasy  and  float 
on  water,  and  are  commonly  faceted  because  of  friction  in  the 
gall-bladder. 

Bile-salts  are  formed  only  in  the  liver.  Bile-pigments  are 
formed  normally  in  the  liver,  but  also  abnormally  from  the 
breaking  down  of  red  corpuscles  and  extravasations  in  other 
parts  of  the  body.  Thus,  there  are  two  kinds  of  jaundice: 
hepatogenous  (usually  obstructive,  with  lymph  absorption)  and 
hematogenous.  Cholemia  leads  to  destruction  of  red  corpus- 
cles and  circulatory  disturbances.  A  diminished  biliary  flow 
into  the  intestine  favors  constipation  and  putrefaction.  The 
total  amount  of  bile,  as  well  as  the  proportion  of  solids,  is  gen- 
erally diminished  in  fevers.  A  little  greenish  bile  is  commonly 
present  in  vomit  when  this  is  frequent  or  severe.  The  presence 
of  bile  in  the  stomach-contents  drawn  with  a  tube  is  suspicious 
of  stenosis  of  the  small  intestine.  The  bile  of  one  day,  injected 
into  the  veins,  would  be  sufficiently  toxic  to  kill  three  men. 

Experiment. — To  some  fresh  ox-bile  in  a  test-tube  add  twice  as 
much  water.  Filter,  if  not  clear,  and  add  acetic  acid.  Note  slight  ppt. 
of  mucin  (more  in  human  bile). 


SECRETIONS.  385 

Experiment.  Test  for  Bile-acids. — Add  to  a  few  c.c.  of  well-diluted 
bile  two-thirds  its  own  volume  of  strong  H2SO4,  letting  the  acid  run 
slowly  down  the  side  of  the  tube  so  as  not  to  mix,  and  keeping  the  tem- 
perature below  70°  C.  Then  add  2  or  3  drops  of  a  10-per-cent.  cane-sugar 
solution,  and  shake  gently.  A  pink,  red,  or  violet  color  develops,  with 
a  pink  foam.  The  reaction  depends  on  the  formation  of  furfurol.  Albu- 
min or  morphin  gives  a  similar  color-reaction. 

Experiment. — Pulverize  a  small  gall-stone  and  dissolve  in  a  mixture 
of  warm  alcohol  and  ether.  Decant  into  an  evaporating  dish  and  allow 
to  evaporate  spontaneously.  Note  the  crystals  under  the  microscope: 
thin,  transparent  plates  with  a  notched  corner. 

Experiment. — Dissolve  in  a  dry  test-tube  a  few  of  the  crystals  in 
CHC13,  add  an  equal  volume  of  H2SO4,  and  shake.  A  blood-red  color  ap- 
pears, turning  cherry  and  purple,  with  a  green  fluorescence. 

PANCREATIC   JUICE. 

The  pancreatic  secretion  is  clear,  thick,  and  strongly  alka- 
line,, and  contains  about  10  per  cent,  of  solid  constituents:  two- 
thirds  organic,  one-third  inorganic.  The  alkalinity  is  due  chiefly 
to  Na2C03. 

Pancreatic  calculi  are  rare  and  consist  mostly  of  phosphate 
and  carbonate  of  calcium,  with  a  nucleus  of  animal  matter. 

INTESTINAL  JUICE. 

The  succus  entericus  is  a  clear,  viscid,  light-yellow,  opales- 
cent, strongly  alkaline  secretion,  containing  a  little  over  2  per 
cent,  of  solids,  of  which  about  one-third  is  inorganic. 

MUCUS. 

The  protective  fluid  of  mucous  membranes  is  a  glossy, 
translucent,  colorless  or  opaque,  stringy,  generally  alkaline 
secretion,  containing  4  or  5  per  cent,  of  solids,  chiefly  mucin. 
Microscopically  it  shows  mucous  corpuscles,  epithelia,  fatty 
granules,  and  sometimes  cholesterin  crystals.  Mucus  varies 
somewhat  according  to  its  place  of  origin.  Thus,  vaginal  mucus 
is  thin  and  acid,  while  that  from  the  neck  of  the  uterus  is  alka- 
line and  resembles  the  white  of  egg. 

Excess  of  mucus  accompanies  irritation  or  inflammation  of 
the  part  affected,  and  favors  fermentation. 

TEARS. 

The  protective  secretion  of  the  lacrymal  glands  is  a  clear, 
slightly  alkaline  fluid,  containing  2  per  cent,  of  solids,  mostly 
NaCl,  albumin,  and  mucus.  The  so-called  tear-stone  is  a  calci- 
fied mass  of  fungus. 


386  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

SEBUM. 

The  lubricating  secretion  of  the  sebaceous  glands  is  an 
oily  semifluid,  which  becomes  a  white,  greasy  solid  on  cooling. 
It  is  composed  of  fat,  soaps,  cholesterin,  nucleo-albumin,  phos- 
phates, chlorids,  and  epithelial  scales.  Obstruction  of  the 
gland-ducts  leads  to  the  formation  of  "black-heads,"  "wens," 
etc.  The  smegma  of  the  external  genitals;  ear-wax,  or  ceru- 
men; and  the  vernix  caseosa  of  newborn  infants  are  sebaceous 
in  character. 

MILE. 

The  nutrient  secretion  of  the  mammary  gland  is  a  natural 
emulsion  of  fat-globules  held  in  suspension  by  casein  and  cal- 
cium phosphate. 


Fig.  48.— Human  Milk  and  Colostrum. 

The  average  daily  quantity  of  milk  from  a  woman  is  about 
a  liter;  from  a  cow,  six  to  ten  liters  (four  times  the  body-weight 
in  a  year).  The  color  is  normally  white  or  light  yellow,  human 
milk  having  more  of  a  bluish  tinge  than  cows'.  Milk  is  colored 
blue  by  the  bacillus  pyocyaneus;  blue,  slimy,  and  bitter  by 
tyrotoxicon;  purple-red  by  the  micrococcus  prodigiosus;  and 
yellow  by  the  bacillus  synxanthus.  It  is  reddish  yellow  in 
rinderpest,  owing  to  the  presence  of  blood.  Eopy  milk  is  caused 
by  a  special  bacillus  during  moist,  warm  weather.  Inflamma- 
tion of  the  udder  imparts  a  salty  taste  to  milk. 

The  reaction  of  cows'  milk  is  usually  amphoteric,  because 
of  the  presence  of  both  acid  and  alkaline  sodium  phosphate. 
Fresh  human  milk  is  generally  feebly  alkaline.  The  sp.  gr. 
of  milk  ranges  from  1.018  to  1.045.  Healthy  human  milk  is 


SECRETIONS.  387 

from  1.028  to  1.033,  with  an  average  of  1.031.  Healthy  bovine 
milk  ranges  from  1.029  to  1.035.  Breast-milk  is  thinner  the 
less  frequently  it  is  taken. 

The  solids  in  milk  amount  to  nearly  13  per  cent,  normally, 
varying  from  8  to  16  per  cent.  These  comprise  chiefly  casein 
(3  per  cent,  in  bovine,  1  per  cent,  in  human),  lactalbumin  (0.5 
per  cent,  in  cows',  1  per  cent,  in  woman's),  fat  (4  per  cent,  in 
woman's,  3.7  per  cent,  in  cows'),  lactose  (6  per  cent,  in  human, 
4.5  per  cent,  in  bovine),  and  mineral  salts  (0.2  per  cent,  in 
woman's,  0.7  per  cent,  in  cows'),  mostly  Ca3(P04)2.  Milk  con- 
tains more  lime  to  the  liter  than  liquor  calcis.  Other  salts  are 
the  phosphates  of  Mg,  K,  and  Na;  the  chlorids  of  K  and  Na; 
and  a  trace  of  iron.  Other  proteins  in  traces  are  lactoglobulin 
(probably  identic  with  serum-globulin),  nuclein,  pepton,  and 
albuminoids.  Still  other  unimportant  ingredients  are  lecithin, 
leucin,  creatin,  and  about  8  per  cent.,  by  volume,  of  gases  (0, 
N,  and  C02).  Milk  is  deficient  in  iron,  but  infants  contain  in 
their  tissues  a  store  of  this  metal  that  is  slowly  used  up  during 
the  period  of  suckling.  The  composition  of  milk  varies  con- 
siderably from  day  to  day,  and  the  strippings  are  seven  times 
as  rich  as  the  first  few  drops. 

The  casein  of  milk  is  not  in  solution,  but  is  held  in  gran- 
ular suspension;  it  can  be  filtered  out  by  a  clay  filter  as  a  fine, 
white  powder.  It  dissolves  readily  in  alkalies  or  mineral  acids, 
and  reddens  moist  litmus-paper.  It  does  not  coagulate  on  boil- 
ing, but,  along  with  Ca,  forms  the  scum.  It  coagulates  quickly 
with  acids  or  lab-ferment  (rennet)  in  the  presence  of  Ca3(POJ2, 
with  which  the  casein  unites  to  form  the  curd  (paracasein),  a 
small  quantity  of  whey  albumose  being  formed  at  the  same 
time.  Human  casein  can  be  pptd.  by  saturating  with  MgS04. 
It  forms  a  finer,  more  flocculent,  and  more  digestible  coagulum 
than  cows'  milk.  Phosphocarnic  acid  is  split  off  from  human 
casein  in  digestion,  and  is  peculiarly  rich  in  P. 

Experiment. — Fill  two  test-tubes  one-half  with  milk,  and  to  one 
add  a  teaspoonful  of  a  good  liquid  rennet.  Let  stand  for  fifteen  minutes. 
Then  boil  the  milk  in  both  tubes.  Note  that  the  milk  containing  the 
rennin  gives  a  flocculent  ppt.,  the  other  a  heavy,  curdy  ppt.  Quite  fresh 
milk  (except  colostrum)  does  not  coagulate  on  heating. 

Lactose  is  nearly  constant  in  quantity  in  the  same  person. 
It  ferments  spontaneously  at  ordinary  temperatures  into  lactic 
acid,  which  removes  the  phosphates  and  ppts.  coagulated  casein, 
forming  the  curd;  the  whey  is  the  thin  liquid  left  after  re- 
moving the  curd.  In  the  curdling  of  milk  there  is  also  a  slight 
evolution  of  C02. 

Butter-fat  appears  in  small,  refractive  globules  0.0015  to 


388  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

0.01  mm.  in  diameter  (average,  3.7  microns)  and  averaging  from 
1  to  5.7  millions  per  c.c.  It  contains  traces  of  lecithin  and 
cholesterin  and  a  little  yellow  coloring  matter  (lipochrome). 

Experiment. — Confirm  existence  of  fat-drop  membrane  by  mixing 
some  milk  with  a  little  KHO  before  shaking  with  ether.  Solution  is 
greatly  aided,  as  is  readily  shown  by  a  blank  test. 

The  laxative  colostrum  of  the  first  few  days  of  lactation  is 
nearly  one-fourth  solids  (sp.  gr.,  1.046  to  1.080),  containing  an 
excess  of  fat  and  proteins  (no  caseinogen)  and  numerous  colos- 
trum corpuscles  (epithelial  cells,  including  fat-globules). 

Mothers'  milk  diminishes  in  fat  and  proteins  near  the 
weaning  period.  A  fatty  diet  diminishes  the  quantity  of  milk. 
A  vegetable  diet  increases  the  sugar  and  decreases  proteins  and 
fat.  Meats  cause  an  increase  in  both  fat  and  proteins.  Exer- 
cise diminishes  proteins,  Hg,  As,  I,  Pb,  Br,  laxative  salts, 
turpentine,  and  volatile  oils  pass  into  the  breast-milk  when 
taken  internally.  Organic  acids  taken  by  the  mother  cause 
griping  in  the  nursing  child.  Worry,  emotions,  and  menstrua- 
tion increase  the  proteins  and  render  the  milk  somewhat  poi- 
sonous to  the  infant.  An  insufficient  milk-supply  is  usually 
best  remedied  by  the  free  ingestion  of  fluids,  especially  broths 
and  gruels.  (See  also  under  "Clinic  Chemistry.'7) 

SEMINAL  FLUID. 

The  secretion  of  the  testicle  is  a  white,  opaline,  viscid  fluid, 
containing,  as  its  essential  principle,  the  spermatozoa,  which  are 
mobile  in  the  alkaline  fluids  of  the  body,  but  soon  lose  their 
power  of  motion  outside  the  body.  Nuclein  is  the  chief  con- 
stituent of  these  cells;  they  also  contain  fat,  lecithin,  and 
cholesterin.  The  glue-like  odor  is  due  to  spermin  (C2H4NH), 
which,  on  standing,  forms  characteristic  dagger,  or  cuttle-bone, 
crystals. 

The  recognition  of  spermatozoa  in  stains  is  best  accom- 
plished, according  to  Simon,  by  soaking  a  fragment  of  the  cloth 
or  scrapings  for  an  hour  or  more  in  a  watch-crystal  containing 
27  to  30  per  cent,  alcohol,  then  teasing  a  bit  of  the  matter  in 
a  1  to  200  solution  of  eosin  in  glycerin,  and  examining  under 
the  microscope.  The  heads  of  the  spermatozoa  are  stained  deep 
red,  the  tails  pale  rose.  Vegetable  fibers  do  not  take  up  this 
stain. 

In  addition  to  the  spermatozoa,  semen  contains  seminal 
and  other  granules,  epithelial  cells,  and  oil-globules.  The  ma- 
jor portion  of  an  ejaculation  consists  of  the  secretion  of  the 
seminal  vesicles,  which  contains  many  mucoid  globules  and 


SECRETIONS. 


389 


some  granular  phosphates.  The  prostatic  secretion  is  a  thin, 
alkaline  liquid,  containing  granular  phosphates,  often  grouped 
in  colored  microscopic  concretions  or  sympexia.  During  sexual 
excitement  Littre's  follicles,  Cowper's  glands,  and  Morgagm's 
crypts  pour  forth  a  clear  mucus  like  white  of  egg.  This  secre- 
tion is  alkaline  in  reaction,  and  neutralizes  and  lubricates  the 
anterior  urethra. 

LYMPH. 

This  is  a  clear,  colorless,  or  faintly  yellow  or  red,  alkaline, 
coagulable   fluid,   which   constitutes   the   interstitial   nutrient 


Fig.  49. — Spermatozoa  and  Bottcher's  Crystals. 

liquid  of  the  body  and  carries  into  the  blood  the  retrogressive 
products  of  metabolism.  It  makes  up  perhaps  one-fourth  the 
weight  of  the  whole  body.  It  varies  considerably  in  composi- 
tion, the  solids  averaging  about  4  per  cent,  (chiefly  albumin, 
fats,  and  NaCl),  and  in  sp.  gr.  from  1.022  to  1.045. 

CHYLE. 

This  is  nearly  identic  with  lymph,  except  during  absorp- 
tion, when  it  contains  considerable  fat  (over  3  per  cent.),  which 
gives  it  a  creamy  appearance,  and  more  fibrin  (0.2  per  cent.). 


390  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

It  is  strongly  alkaline,  and  has  a  sp.  gr.  of  1.007  to  1.022.  It 
is  the  mother-liquid  of  the  blood.  As  it  passes  from  the  intes- 
tine into  the  receptacuhim  chyli  it  loses  albumin  and  fat  and 
takes  up  corpuscles  and  fibrin,  thus  becoming  coagulable. 

CEREBRO-SPINAL   FLUID. 

The  meningeal  fluid  obtained  by  lumbar  puncture  is  clear 
(unless  purulent)  and  frankly  alkaline;  sp.  gr.,  1.006  to  1.007. 
It  contains  less  than  2  per  'cent,  of  solids,  chiefly  K  and  Na 
salts  and  more  or  less  albumin — above  1  per  cent,  in  severe 
inflammations.  Sugar  is  present  in  cases  of  brain-tumor. 

SYNOVIA!  FLUID. 

The  synovia  is  a  clear,  light-yellow,  mucoid,  alkaline  fluid, 
containing  from  3  to  5  per  cent,  of  solids:  mucin,  albumin,  fat, 
and  salts.  The  consistency  of  the  liquid  is  increased  by  much 
use  of  the  joint. 

INTERNAL   SECRETIONS. 

By  this  term  is  meant  the  specific  non-excretory  substances 
formed  within  glandular  organs  and  given  off  directly  to  the 
blood  or  lymph.  Like  the  secretions  having  external  commu- 
nication, these  have  a  special  function  in  the  maintenance  of 
health. 

The  formation  in  the  liver  and  muscles  of  glycogen  from 
dextrose,  and  the  reverse  change,  are  among  the  most  impor- 
tant examples  under  this  heading.  Experiments  on  animals 
and  autopsies  on  the  human  body  seem  to  prove  that  the  pan- 
creas furnishes  the  blood  or  lymph  with  an  internal  secretion 
necessary  either  to  the  normal  consumption  of  sugar  in  the 
body  or  to  the  control  of  the  sugar  output  from  the  liver  and 
muscles. 

The  function  of  the  thyroids  appears  to  be  connected  with 
metabolism,  and  when  the  glands  are  extirpated  or  atrophied 
the  subject  becomes  diseased  (myxedema)  and  succumbs.  The 
essential  secretion  of  the  thyroid  is  thyroidalbumin,  from  which 
thyroidin  is  obtained  by  boiling  with  acids.  Dry  thyroidin  is 
an  organic  compound  containing  nearly  10  per  cent,  of  I. 

Suprarenal  extract  is  a  true  internal  secretion,  and  is  a 
most  powerful  vascular  tonic.  Hence  it  is  used  for  preventing 
and  controlling  hemorrhages.  The  active  principle  of  the  ex- 
tract is  a  pyrrol  derivative  called  epinephrin,  or  adrenalin. 

The  pituitary  body  is  claimed  by  some  authors  to  furnish 
an  internal  secretion  relating  to  body-growth.  The  testes, 


EXCRETIONS.  391 

ovaries,  and  other  glands  are  also  thought  to   exert  special 
effects  on  the  organism  through  internal  secretions. 


EXCRETIONS. 

Excreta  differ  from  true  secreta  in  consisting  chiefly  of 
waste-products  which  are  no  longer  of  any  service  to  the  or- 
ganism. They  pre-exist  in  the  blood  and  accumulate  in  this 
fluid  if  not  properly  eliminated,  giving  rise  to  symptoms  of 
poisoning.  The  principal  waste-products  of  the  human  econ- 
omy are  urea,  C02,  H20,  NH3,  the  purin  bodies,  creatin,  the 
inorganic  sulphates  and  phosphates,  the  conjugate  sulphates, 
and  various  pigments.  The  amount  of  urea  excreted  Varies 
from  2  or  3  grains  per  pound  daily  in  sedentary  adults  to  3  1/2 
grains  per  pound  in  active  workers,  and  6  to  10  grains  per 
pound  in  children. 

URINE. 

This  is  the  most  important  excretion,  containing,  as  it 
does,  nearly  all  the  urea.  The  water  and  inorganic  salts  of 
the  urine  appear  to  be  eliminated  by  simple  osmosis  and  dif- 
fusion from  the  capillary  tufts  of  the  glomeruli.  The  urea  is 
secreted  by  a  special  selective  action  of  the  cells  lining  the 
convoluted  tubules.  When  the  nutrition  of  these  cells  is  im- 
paired by  inflammation,  malnutrition,  or  other  causes,  the  urea 
is  not  fully  excreted,  and  accumulates  in  the  blood  (uremia), 
while  albumin  and  globulin  escape  from  the  blood  into  the 
urine.  (See  also  under  "Clinic  Chemistry.") 

FECES. 

The  alvine  evacuations  consist  chiefly  of  water  (75  per 
cent.);  insoluble  and  indigestible  residues  (7  per  cent.)  of 
cellulose,  resins,  and  albuminoids;  inorganic  salts  (1.2  per 
cent.);  mucus  (12  per  cent.);  epithelia,  fat-drops  and  fatty- 
acid  crystals,  cholesterin,  indol,  skatol,  phenol,  cresol,  extract- 
ives, and  bacteria.  The  daily  solids  should  amount  to  30  to 
60  gm.  The  gases  (CH4,  H,  N,  and  C02)  are  most  abundant 
on  a  vegetable  diet. 

The  reaction  of  feces  is  normally  neutral  or  slightly  alka- 
line (normally  acid  in  infants);  occasionally  acid  from  fatty- 
acid  fermentation;  rarely  quite  alkaline,  with  triple  phosphates, 
in  typhoid  and  dysentery  (with  free  bile  and  much  chlorids  and 
albumin). 

The  peculiar  feculent  odor  is  due  to  the  putrefactive  prod- 
ucts (from  tyrosin),  indol  (C8H7N),  and  skatol  (C9H8N),  along 


392  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

with  H2S,  H3P,  and  butyric  and  valeric  acids.  A  meat  diet 
makes  the  stools  smell  stronger.  The  extremely  foul  odor  of 
naphthylamin  is  sometimes  noted  after  eating  fish.  Acholic 
stools  are  generally  fetid  in  odor.  In  the  green,  acid  diarrhea 
of  infants  from  fermentation  of  carbohydrates  the  feces  smell 
sour.  In  the  more  severe  leaden-gray,  pultaceous  form  a  putrid 
odor,  due  to  albuminous  putrefaction,  is  noted.  The  charac- 
teristic odor  of  cadaverin  is  marked  in  dysenteric  and  choleraic 
evacuations.  In  the  gangrenous  variety  of  dysentery  and  in 
syphilitic  and  carcinomatous  rectal  ulceration  there  is  a  very 
offensive  rotten  stench. 

The  color  of  the  stools  varies  from  light  yellow  (alkaline 
diet)  to  dark  brown  (meat  diet),  and  depends  normally  on 
changed  bile-pigment  (stercobilin).  The  green  color  noted  in 
summer  diarrhea  may  be  caused  either  by  biliverdin  or  by  the 
green  bacillus  of  le  Sage.  Excess  of  unchanged  bile  makes  the 
color  green.  When  the  bile  is  deficient  the  stools  are  pasty 
and  clayey  in  color.  White,  fatty  stools  also  accompany  pan- 
creatic disease.  Undigested  casein  often  appears  in  white 
lumps  in  the  discharges  of  infants.  After  taking  calomel  or 
ipecac  the  stools  are  spinach-green.  Fe,  Mn,  Bi,  and  Pb  salts 
darken  the  stools,  owing  to  the  formation  of  the  sulphid  or  oxid 
of  the  metal.  Santonin,  rhubarb,  and  senna  cause  yellow  stools. 
Starch  tends  to  produce  a  yellowish  tinge;  .chlorophyl,  a  green; 
cocoa,  a  gray;  red  wine,  blackish. 

The  evacuations  are  serous  in  cholera  infantum.  The  rice- 
water  appearance  of  albuminous  cholera  feces  is  due  to  large 
numbers  of  epithelia.  Catarrhal  conditions  are  accompanied  by 
excess  of  mucus,  sometimes  forming  pseudocasts  of  the  bowel. 
Mucus  from  the  small  intestine  is  well  mixed  with  the  feces. 

Blood  in  the  stools  is  bright  colored  if  from  the  large  in- 
testine; dark  and  tarry  (hematin),  from  the  stomach  or  small 
intestine.  Blood  and  pus  appear  in  dysentery,  ulcerative  con- 
ditions generally,  and  perforations  of  extra-intestinal  abscesses. 

Leucin  and  tyrosin  are  found  in  cholera  feces.  Urea  is 
excreted  in  considerable  quantities  by  the  intestine  in  uremic 
conditions.  It  quickly  changes  to  ammonium  carbamate,  which 
by  its  irritating  action  on  the  mucous  membrane  causes  the  so- 
called  critic  diarrhea  and  vomiting.  In  constipation  and  fecal 
impaction  water  is  reabsorbed  and  the  excrement  forms  hard 
scybala  with  mucus. 

The  viscid  meconium  of  the  newborn  owes  its  dark  color 
to  altered  bile.  Micro-organisms  and  their  spores  are  absent 
till  after  suckling. 

Intestinal  concretions,  bezoar,  or  enteroliths,  are  rarely 


EXCRETIONS.  393 

met  with  in  human  subjects.  They  may  consist  chiefly  of 
earthy  phosphates,  of  fatty  matters,  of  hairs,  of  vegetable  fibers 
(oatmeal),  or  of  insoluble  medicines  (bismuth  salts). 

SWEAT. 

The  average  daily  amount  of  perspiration  is  from  700  to 
900  c.c.  It  is  a  highly-aqueous  liquid,  containing  only  1.2  per 
cent,  of  solids  and  having  a  sp.  gr.  of  1.004.  The  chief  solids 
are  the  alkaline  chlorids  (especially  NaCl),  sulphates  and  phos- 
phates, cholesterin,  urea,  and  epithelia.  The  fatty  acids  (acetic, 
formic,  propionic,  caproic),  ethereal  sulphates,  and  purin  bodies 
are  present  when  sweating  is  profuse.  About  2  gm.  of  C02  is 
given  off  by  the  skin  in  twenty-four  hours.  The  amount  of 
urea  excreted  by  this  route  is  markedly  increased  in  uremic 
conditions,  and  glistening  crystals  of  the  compound  may  some- 
times be  seen  on  the  skin;  vapor-baths  have  the  same  effect. 

Freshly  excreted  sweat  is  usually  slightly  alkaline  in  reac- 
tion, but  may  be  acid.  It  may  be  colored  yellowish  from  bile, 
blue  from  indican,  red  from  blood.  It  is  very  acid  in  acute 
rheumatism  and  in  rickets.  It  is  strongly  alkaline  (ammoniacal) 
in  uremia. 

lodin,  iodids,  organic  acids,  and  other  drugs  may  appear 
in  the  sweat  after  their  administration.  The  skin  eruptions 
sometimes  following  the  ingestion  of  berries  and  shell-fish  may 
be  caused  by  the  local  irritation  of  organic  acids  and  intestinal 
decomposition  products.  The  ill  effects  of  coating  the  skin 
with  varnish  are  due,  not  to  checking  of  perspiration,  but  to 
resulting  dilation  of  cutaneous  vessels  and  consequent  loss  of 
heat. 

VOMIT. 

Vomiting  of  undigested  food  some  hours  after  meals  is 
noted  in  gastric  atrophy  or  anadeny.  Vomiting  of  well-digested 
food  occurs  in  stomach  neuroses,  gastric  ulcer,  and  acute  or 
subacute  gastritis  and  in  central  emesis.  Morning  vomiting  of 
food  taken  the  day  before  indicates  some  interference  with  gas- 
tric motility,  usually  accompanied  by  dilation  and  fermentation. 
Morning  vomiting  also  occurs  in  alcoholic  subjects  and  patients 
with  chronic  pharyngitis,  from  the  swallowing  of  mucus  and 
saliva.  Bile  and  pancreatic  juice  are  nearly  always  present  in 
vomit  when  severe  or  protracted,  and  the  former  is  readily  dis- 
tinguished by  its  color. 

Bright  blood  is  characteristic  of  gastric  ulcer,  in  which 
considerable  quantities  are  lost.  Small  amounts  of  blood  are 
changed  to  hematin  by  the  acid  gastric  juice,  giving  rise  to  the 


394  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

black,  or  "coffee-ground,"  ejections  of  gastric  cancer  and  he- 
patic cirrhosis.  Pus  in  vomit  is  generally  due  to  the  perforation 
into  the  stomach  of  an  adjoining  abscess. 

Stercoraceous  vomiting  is  easily  recognized  by  the  odor, 
and  is  indicative  of  intestinal  obstruction.  A  feculent  odor  is 
also  sometimes  observed  in  cases  of  enterostenosis  and  in  sub- 
jects with  a  fistula  between  the  stomach  and  the  intestine. 

The  odor  of  vomit  may  be  putrid  in  gastric  carcinoma  and 
in  pyloric  obstruction  from  any  cause.  An  ammoniacal  odor  is 
observed  in  uremic  vomiting;  a  garlicky  odor  in  P  poisoning; 
carbolic  and  hydrocyanic  acids  give  characteristic  scents  to  the 
vomit. 

The  regurgitated  material  from  an  esophageal  sac  or  strict- 
ure is  easily  distinguished  from  true  vomit  by  the  total  absence 
of  all  gastric  elements. 

SPUTUM. 

The  chemistry  of  the  sputum  is  of  no  great  relative  im- 
portance. The  daily  quantity  may  exceed  a  pint  in  cases  with 
large  cavities.  The  color  and  opacity  depend  chiefly  on  the 
contained  leucocytes. 

The  following  crystals  are  occasionally  met  with:  Hema- 
toidin  (following  extravasations  of  blood),  cholesterin  (stag- 
nant pus),  fatty-acid  needles  (putrid  conditions),  calcium  oxa- 
late,  triple  phosphates,  leucin,  tyrosin,  and  the  Charcot-Leyden 
crystals.  These  last  are  long,  sharp  octahedra,  having  the  for- 
mula C2H5N.  They  are  most  frequently  observed  in  asthma, 
and  are  chemically  identic  with  spermin.  They  represent  a 
retrogressive  cellular  metamorphosis  and  are  found  in  decom- 
posing viscera. 

Particles  of  silica  or  stone-dust  are  observed  in  chalicosis; 
of  coal-dust  in  anthracosis;  of  iron  in  the  siderosis  of  grinders; 
and  of  kaolin  in  the  sputum  of  potters  and  brick-makers. 
CaC03  concretions  may  come  from  the  tonsillar  crypts  or  from 
old  pulmonary  cavities,  and  the  same  is  true  of  fetid  cheesy 
particles.  Earely  a  blue  tinge  is  noted  in  tuberculous  sputum, 
due  to  ferrous  phosphate. 

CYSTIC   CONTENTS. 

Ovarian  and  parovarian  cysts  may  contain  either  a  clear, 
straw-colored  fluid  (red-brown  if  hemorrhagic)  of  low  sp.  gr. 
and  with  little  albumin,  or  a  dense,  glairy,  colloid  material 
(1.018  to  1.024)  with  a  large  amount  of  serum-albumin,  serum- 
globulin,  and  metalbumin.  This  last  protein  is  very  character- 
istic of  ovarian  cysts.  It  may  be  demonstrated,  according  to 


EXCRETIONS.  395 

Simon,  by  mixing  the  fluid  with  three  times  its  volume  of  alco- 
hol, setting  aside  for  twenty-four  hours,  and  filtering.  The 
filtrate  on  boiling  becomes  cloudy,  without  a  ppt.,  however. 
It  gives  no  ppt.  with  acetic  acid,  but  with  this  acid  and  potas- 
sium ferrocyanid  thickens  and  turns  yellowish.  H2S04  gives  a 
violet  color,  and  boiling  with  Millon's  reagent  a  bluish  red. 
Cholesterin  crystals  are  generally  quite  numerous. 

Hydatid  fluid  is  clear,  alkaline,  and  non-albuminous;  sp.  gr. 
1.006  to  1.010.  NaCl  is  abundant,  and  succinic  acid  is  usually 
present.  Seeing  the  characteristic  booklets  under  the  micro- 
scope is  the  final  test. 

The  fluid  of  pancreatic  cysts  is  recognized  by  its  power  of 
digesting  albumin  in  alkaline  solutions.  Milk  may  be  employed 
as  a  test-medium,  using  the  biuret  reaction  after  pptg.  the 
casein.  A  negative  result  does  not  exclude  a  pancreatic  origin, 
since  trypsin  is  not  present  in  very  old  cysts. 

The  finding  of  urea  in  notable  quantities  readily  distin- 
guishes a  hydronephrotic  cyst  from  any  other,  even  when  the 
liquid  has  no  urinous  odor.  Eenal  epithelial  cells  are  also  quite 
characteristic. 

TRANSLATES  AND   EXTTDATES. 

The  pathologic  accumulation  of  fluids  in  the  serous  cavi- 
ties and  areolar  connective  tissue  (under  skin  and  between 
muscles)  is  termed  an  exudate  when  inflammatory  in  origin;  a 
transudate  when  non-inflammatory  (heart,  blood,  or  kidney 
diseases).  The  sp.  gr.  of  exudates  ranges  from  1.018  to  1.030 
(the  older,  the  denser);  of  transudates  from  1.005  to  1.015. 
The  difference  is  attributed  to  the  amount  of  albumin:  4  to  6 
per  cent,  in  exudates,  1  to  2  per  cent,  in  transudates.  Bxudates 
often  coagulate  spontaneously  after  standing  twenty-four  hours; 
transudates  do  not  coagulate  unless  from  the  presence  of  blood. 
Considerable  gas,  chiefly  C02,  is  frequently  developed  in  these 
fluids. 

Transudates  are  generally  serous  and  of  a  light-straw  color 
(tinged  reddish  if  blood  is  present);  rarely  they  are  chylous. 
Hydrocele  fluid  contains  nearly  5  per  cent,  of  serum-albumin 
and  serum-globulin.  Plates  of  cholesterin  are  often  found  in 
old  serous  transudations.  Anasarcal  fluid  is  clear  and  watery 
(1.005  to  1.010),  and  contains  about  0.5  per  cent,  serum-albu- 
min and  0.1  or  0.2  of  urea.  Ascitic  fluid  is  yellowish,  has  a  sp. 
gr.  of  1.008  to  1.012,  and  contains  from  0.7  to  0.9  per  cent,  of 
inorganic  matter.  It  is  chylous  in  tubercular  peritonitis. 

Exudates  may  be  serous,  serofibrinous  (serosanguinolent), 
seropurulent,  purulent,  putrid,  hemorrhagic,  or  chylous.  Serous 


396  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

exudates  resemble  transudates,  and  have  a  sp.  gr.  usually  above 
1.008.  Hemorrhagic  exudates  into  the  pleura  are  most  fre- 
quent in  cases  of  pulmonary  tuberculosis  and  carcinoma,  which 
are  distinguished  from  each  other  by  finding  cancer-cells  and 
fat-droplets  in  the  latter  instance;  tubercular  exudates  are 
usually  sterile. 

Putrid  exudates  are  brown  or  greenish  brown  and  alkaline 
(except  from  perforation  of  gastric  ulcer),  and  are  readily  rec- 
ognized by  the  odor.  Purulent  exudates  vary  in  color  from 
gray-yellow  to  green-yellow,  and  in  sp.  gr.  from  1.020  to  1.040. 
They  are  alkaline  when  fresh  (pleural  may  be  weakly  acid),  and 
have  the  same  chemic  composition  as  white  blood-corpuscles, 
with  addition  of  pepton.  Empyema  following  pneumonia  is 
likely  to  contain  large  clumps  of  fibrin.  Leucin  and  tyrosin 
are  often  present  in  old  abscesses. 

The  fluid  from  uterine  cysts  differs  from  amniotic  liquid 
in  containing  more  albumin  and  but  a  trace  of  urea.  This  dis- 
tinction is  of  some  importance  as  regards  watery  discharges 
from  the  uterus  during  pregnancy. 


ANIMAL    FUNCTIONS. 

All  the  phenomena  of  the  living  body  are  caused  directly 
or  indirectly  by  chemic  changes.  Every  pulse,  every  breath, 
action,  and  thought  involves  intricate  reactions,  which  are  more 
or  less  imperfectly  understood. 


DIGESTION. 

The  process  of  digestion  consists  essentially  of  hydrolysis: 
i.e.,  the  taking  up  of  water  by  food-products  and  their  breaking 
down  into  simpler  molecules  capable  of  diffusion.  The  end- 
product  of  amylolytic  digestion  is  dextrose;  of  proteolytic,  pep- 
ton  or  amido-acids.  Fats  are  simply  saponified  and  emulsified. 
The  mixed  acid  products  of  digestion  in  the  stomach  are  termed 
chyme.  The  reaction  becomes  alkaline  (latter  part  of  digestion) 
by  the  middle  of  the  small  intestine  and  remains  so  to  the  ileo- 
cecal  valve;  it  is  often  acid  below  this  point,  owing  to  fermenta- 
tion. Peptons  stimulate  gastric  secretion. 

A  piece  of  well-masticated  bread  is  changed  by  the  ptyalin 
of  the  saliva  into  amylo-,  erythro-,  achroo-,  and  malto-  dextrin, 
and  partly  into  maltose.  The  amylolytic  action  of  the  saliva 
continues  in  the  stomach  for  about  a  half-hour  after  the  food 
is  swallowed,  or  until  the  acid  gastric  juice  permeates  the  whole 


DIGESTION.  397 

mass.  The  conversion  of  starches  into  maltose  is  completed 
by  the  amylopsin  of  the  pancreatic  juice,  which  is  by  far  the 
most  active  digestive  secretion  in  the  body.  The  maltose  and 
any  cane-sugar  or  lactose  which  may  have  been  present  in  the 
bread  are  inverted  by  the  invertase  (maltase  or  lactase)  of  the 
intestinal  juice. 

The  butter  on  the  bread  is  not  affected  by  saliva,  but  is 
liquefied  by  gastric  juice,  which  seems  to  break  down  the  mem- 
branes of  the  fat-drops,  causing  them  to  run  together.  In  the 
duodenum  it  is  acted  on  by  both  the  bile  and  the  pancreatic 
juice.  The  steapsin  of  the  latter  cleaves  oils  and  fats  into  glyc- 
erin and  fatty  acids.  These  latter  form  a  little  soft  soap  with 
Na2C03,  and  the  soap  emulsifies  the  remaining  fats.  The  action 
of  the  bile  is  similar. 

C3H5(C18H3502)3  +  3H20  =  3C3H5(OH)3  +  3HC18H3502 

A  piece  of  meat  or  an  egg  is  first  changed  to  syntonin 
by  the  gastric  HC1,  then  to  albumoses  (proto-,  hetero-,  and 
deutero-,  or  secondary),  and  finally  to  amphopeptons  (hemi- 
and  anti-;  half  and  half  in  vitro;  anti-  much  exceed  hemi-  in 
intestine),  the  last  change  being  effected  chiefly  by  the  trypsin 
of  the  pancreatic  juice.  Fibrin  swells  up,  becomes  transparent, 
and  is  corroded  by  the  gastric  juice;  by  trypsin  it  is  first 
changed  to  globulin. 

Albumoses  differ  according  to  the  proteins  from  which 
they  were  derived,  and  are  often  designated  as  globulinose, 
caseose,  etc.  Peptons  are  pptd.  by  the  bile-salts,  thus  favoring 
absorption.  Hemipeptons  are  converted  by  trypsin  and  erepsin 
into  leucin,  tyrosin,  and  tryptophan.  This  last,  also  known  as 
proteino-chromogen,  is  related  to  bilirubin  and  melanin,  and 
may  be  utilized  in  building  up  hemoglobin  and  other  pigments. 
It  gives  a  purple-red  color  with  Br  water.  Antipepton,  C10H15- 
N305,  is  isomeric  with  sarkinic  acid,  from  the  phosphosarkinic 
acid  of  muscles.  It  resists  the  change  into  leucin  and  tyrosin. 

Milk  undergoes  similar  digestive  changes  to  the  three  men- 
tioned above,  with  the  addition  of  a  curdling  process  due  to 
chymosin.  Connective  tissue  is  digested  by  the  gastric  juice, 
but  not  by  the  pancreatic.  Nucleo-proteids  leave  a  residue  of 
nuclein,  called  dyspepton  in  the  case  of  fibrin.  Keratin  is  alto- 
gether indigestible. 

Experiment. — Digest  in  three  porcelain  dishes  by  means  of  (1) 
pepsin  and  (2  and  3)  pancreatin,  a  small  disk  of  egg-albumin,  a  dram 
of  hydrated  (boiled)  starch,  and  a  few  c.c.  of  codliver-oil.  Test  con- 
tents of  first  dish  frequently  for  the  digestive  products  syntonin,  albu- 
mose,  and  pepton;  of  the  second  for  dextrins,  maltose,  and  dextrose; 


PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

and  note  rapid  saponification  and  emulsification  of  oil.  The  pepsin  dish 
is  best  kept  in  a  thermostat  at  38°  to  40°  for  two  hours  or  more.  The 
amylolytic  process  can  be  finished  at  about  the  body-temperature  in  less 
than  a  half-hour.  Take  care  not  to  heat  much  above  this  point. 

Intestinal  bacteria  aid  somewhat  in  digestion,  especially 
the  liquefying  ones,  but  their  chief  action  consists  in  the  pro- 
duction of  skatol,  indol,  phenol,  cresol,  NH3,  H2S,  leucin, 
tyrosin,  aspartic  acid,  and  tryptophan  from  proteins;  lactic  and 
butyric  acids  from  starches  and  sugars;  fatty  acids  from  fats; 
and  CH4  and  C02  from  cellulose.  The  chief  fermentation  prod- 
ucts in  the  stomach  are  alcohol  and  lactic,  acetic,  and  butyric 
acids. 


ABSORPTION. 

The  process  of  absorption  depends  on  osmosis  and  diffusion 
and  on  a  special  action  of  the  cells  of  the  alimentary  mucous 
membrane.  Alcohol,  sugar,  and  many  medicines  are  absorbed 
to  some  extent  from  the  mouth,  stomach,  and  rectum,  but  the 
small  intestine  is  the  chief  route  of  entrance  for  alimentary 
products.  Water  is  not  absorbed  from  the  stomach. 

Proteins  are  absorbed  into  the  blood  and  lymph  as  dif- 
fusible amphopeptons,  albumoses,  and  amido-acids,  which  are 
dehydrated  and  regenerated  (polymerized)  by  the  gastric  and 
the  intestinal  mucous  membrane  into  the  colloid  serum-albumin 
and  globulins  of  the  blood.  The  direct  injection  into  the  blood 
of  proteoses  or  peptons  has  a  toxic  effect,  and  large  doses  may 
produce  coma  or  even  death. 

Carbohydrates  are  taken  up  by  the  rootlets  of  the  portal 
vein  and  carried  to  the  liver  chiefly  as  dextrose;  but  maltose, 
levulose,  and  lactose  may  also  reach  absorption  in  small  quan- 
tities. The  glucose  is  stored  in  the  liver  as  glycogen,  and  is 
given  off  again  gradually  as  dextrose  to  the  muscles  and  other 
tissues.  Senility,  obesity,  toxins,  neurasthenia,  and  the  gouty 
habit  all  interfere  more  or  less  with  the  glycogenic  function  of 
the  liver  or  sugar  consumption  by  the  tissues,  and  may  lead 
to  glycosuria  or  diabetes  mellitus.  Experimental  nervous  le- 
sions (floor  of  fourth  ventricle)  and  injuries  to  the  head  cause 
a  sudden  expulsion  of  glycogen  from  the  liver,  with  glycosuria. 
The  most  constant  organic  lesion  in  true  diabetes  is  pancreatic 
disease.  The  ingestion  of  a  large  amount  of  sugar  may  cause 
temporary  alimentary  glycosuria,  whereas  starch  has  no  such 
effect.  Cane-sugar  injected  directly  into  the  blood  cannot  be 


ABSORPTION.  399 

utilized  by  the  tissues,  and  it  passes  out  unchanged  in  the 
urine. 

Fats  are  absorbed  by  the  lacteals  almost  entirely  in  the 
form  of  a  fine  emulsion  or  chyle.  Free  fatty  acids  and  soaps 
appear  to  be  regenerated  into  fats  during  their  absorption 
under  normal  conditions.  The  bile  greatly  aids  the  absorption 
of  fats  by  its  lubricating  action  on  the  mucous  membrane. 
Hence  in  liver  disease  there  is  much  waste  of  fat  in  the  stools. 
In  disease  of  the  pancreas  fat  absorption  ceases,  except  in  the 
case  of  milk,  a  natural  emulsion. 

Highly  crystalline  substances  (KI,  LiCl)  are  absorbed 
within  five  to  fifteen  minutes  after  their  administration  by  the 
mouth.  Others — salol  and  keratin-coated  pills,  for  example — 
are  not  acted  on  by  the  gastric  juice  and  are  not  absorbed  from 
the  intestine  and  found  present  in  the  urine  for  two  hours  or 
longer.  The  gastric  HC1  appears  to  hinder  exosmosis.  Strych- 
nin solutions  are  absorbed  more  quickly  from  the  rectum  than 
from  the  stomach.  During  the  passage  of  the  contents  through 
the  large  intestine — a  period  of  twelve  to  twenty-four  hours — 
much  water  and  some  nutriment  is  absorbed  from  them.  The 
rectum  and  colon  are  able  to  absorb  undigested  nutrient  ene- 
mata,  such  as  eggs,  milk,  and  salt,  though  no  enzyme  is  found 
here.  The  limit  of  absorption  of  egg-albumin  from  this  loca- 
tion is  about  50  grams  daily. 

Any  substance  to  be  absorbed,  generally  speaking,  must 
be  in  the  liquid  or  gaseous  state,  but  finely  divided  charcoal 
taken  internally  has  been  found  in  the  mesenteric  veins.  The 
rate  of  absorption  varies  inversely  with  the  density  of  solution. 
Concentrated  saline  solutions  cause  more  effusion  from  the 
blood-vessels  than  absorption  into  these;  hence  such  hydragog 
purgatives  as  Epsom  salts  should  be  given  in  a  minimum  of 
water  to  get  the  best  effects. 

Absorption  is  aided  by  low  blood-pressure,  and  the  saline 
infusions  injected  into  the  rectum  or  subcutaneously  in  cases 
of  shock  or  hemorrhage  are  drunk  up  greedily  by  the  vessels. 
Obviously  the  more  rapid  the  circulation,  the  more  quickly  ab- 
sorption proceeds.  Absorption  from  the  stomach  is  facilitated 
by  the  use  of  condiments.  Medicines  administered  hypodermic- 
ally  are  taken  into  the  circulation  very  quickly  unless  the  tis- 
sues are  water-logged.  Absorption  through  the  unabraded  skin 
seldom  takes  place  unless  rubbing  is  employed,  as  in  mercurial 
inunctions.  The  absorption  of  poisonous  gases  (HCN)  through 
the  lungs  is  the  most  rapid  cause  of  death. 


400  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 


METABOLISM. 

The  anabolic  or  constructive  chemic  processes  of  assimila- 
tion by  which  the  end-products  of  digestion  become  bone  and 
flesh  and  gland  and  nerve  still  possess  more  of  mystery  than 
of  knowledge.  From  the  transuded  blood,  or  lymph,  the  parent 
fluid  or  soil,  each  differentiated  protoplasmic  portion  of  the 
organism  takes  those  elements  which  are  needed  for  its  _  sus- 
tenance and  structure,  generally  a  loose  and  unstable  combina- 
tion of  specially  modified  proteins,  with  inorganic  salts.  It  is 
a  curious  fact  that  each  of  the  circulating  proteins  shows  minor 
differences  when  the  blood  is  taken  from  different  parts  of  the 
body.  Catabolism  includes  oxidation  and  hydrolysis;  anabo- 
lism,  dehydrolysis. 

Protein  foods  and  salts  are  absolutely  necessary  for  tissue- 
building.  Carbohydrates  are  essentially  producers  of  energy 
and  heat.  They  can  be  formed  -from  fats  or  proteins.  The 
body-fat  is  derived  chiefly  from  carbohydrates;  to  a  minor 
degree  from  other  fats  and  proteins  (lack  of  oxygen).  The 
adipose  tissues  serve  chemically  as  potential  reservoirs  of  heat. 
Albuminoids,  such  as  gelatin,  save  the  tissues  more  than  carbo- 
hydrates do.  Food-products  may  be  said  to  crowd  out  the 
waste-products  from  the  cells,  forming  new  molecules,  which 
speedily  undergo  dissolution  in  a  continually  recurring  cycle. 

The  oxidation  of  these  complex  molecules,  chiefly  in  the 
tissues  (perhaps  some  fuel  foods,  such  as  alcohol  and  glucose, 
are  partly  burned  in  the  capillaries),  gives  rise  to  animal  heat 
and  mechanic  energy  as  results,  and  as  products  the  simple  and 
more  stable  compounds,  such  as  C02,  H20,  NH3,  and  urea.  In 
other  words,  potential  energy  becomes  kinetic  through  the 
agency  of  protoplasm,  with  catabolic  or  destructive  phenomena, 
Tissue  or  bioplasm  proteid  is  supposed  to  break  down  at  the 
rate  of  about  1  per  cent,  per  diem.  An  acid  reaction  quickly 
destroys  the  irritability  of  bioplasm.  Inorganic  salts  normally 
neutralize  the  acids  formed  by  metabolism. 

These  two  opposite  processes  of  anabolism  and  catabolism 
go  on  constantly  and  almost  simultaneously,  and  the  life  of  the 
cell  depends  on  the  intramolecular  atomic  movements.  Accord- 
ing to  Pfliiger,  in  the  living  molecule  N  exists  in  the  form  of 
an  unstable  CN  compound,  which  has  the  power  to  convert 
dead  to  living  labile  proteid  by  a  process  similar  to  polymeriza- 
tion or  condensation.  Catabolism,  or  the  breaking  down  of 
living  labile  proteids,  has  been  likened  to  putrefaction,  with 
the  evolution  of  N",  H,  and  C,  which  combine  with  0  and  with 
each  other  to  form  the  simple  end-products  NH3,  H20,  and 


METABOLISM.  401 

C02.  Living  protoplasm  is  believed  to  consist  of  "larger,  sec- 
ondary units'"  (physic  or  physiologic  molecules,  somacules), 
"each  of  which  is  a  definite  aggregation  of  chemic  molecules, 
and  possesses  certain  properties  or  reactions  that  depend  upon 
the  mode  of  arrangement."  These  somacules  are  suspended  in 
a  saline,  alkaline,  electrolytic  fluid,  and  the  protoplasm  can  be 
changed  through  gellation  from  the  state  of  a  hydrosol  to  that 
of  hydrogel  by  heat,  acids,  electricity,  or  the  abstraction  of 
water.  The  recent  researches  of  Loeb  and  Mathews  point  to 
the  proposition  that  what  we  know  as  life  is  in  the  main  an 
electrochemic  phenomenon  due  to  the  gellation  of  protoplasm 
and  the  liberation  of  free-moving  ions  of  different  valences,  the 
cations  being  inhibitory,  the  anions  stimulating  in  their  phys- 
iologic effects. 

Experiment. — Add  a  little  indigo-blue  to  a  cane-sugar  solution. 
The  indigo  is  reduced  by  the  sugar  and  loses  its  color  (indigo-white). 
On  shaking  with  free  access  of  air  the  color  is  restored. 

Muscular  energy  is  accompanied  by  increased  oxidation  of 
fats  and  carbohydrates  (glycogen),  with  no  appreciable  increase 
in  proteid  metabolism  if  the  food-supply  is  sufficient.  The 
amount  of  C02  eliminated  during  ordinary  muscular  work  is 
nearly  double  that  while  resting.  Glycogen  and  the  circulating 
glucose  diminish  or  disappear  from  the  active  muscle,  lactic 
acid  being  found. 

Four-fifths  of  the  energy  liberated  by  chemic  changes  dur- 
ing muscular  contractions  appears  as  animal  heat,  and  the 
remaining  fifth  of  mechanic  energy  in  the  case  of  the  cardiac 
and  respiratory  muscles  is  also  converted  into  heat.  The 
glands,  particularly  the  liver,  generate  considerable  heat,  and 
the  brain  and  nerves  liberate  no  small  amount  when  in  action. 
Animal  heat  depends  primarily  on  the  oxidation  of  fats,  carbo- 
hydrates, and  proteins  in  the  capillaries  (slightly,  especially  the 
pulmonary)  and  the  tissues,  with  formation  of  C02,  H20,  NH3, 
urea,  etc.,  in  a  somewhat  analogous  manner  to  the  production 
of  smoke,  steam,  and  ashes  by  the  engine.  About  four  times 
as  much  heat  is  radiated  from  the  skin  as  passes  off  from  the 
lungs  and  in  the  urine  and  feces.  About  one-seventh  of  the 
body-heat  is  rendered  latent  by  evaporating  the  perspiration; 
1  gm.  water  =  0.582  calorie. 

The  total  available  potential  energy  of  any  foodstuff  is 
readily  estimated  by  burning  a  certain  quantity  in  a  calorimeter, 
which  is  a  sort  of  furnace  surrounded  by  a  given  weight  of 
water.  From  the  rise  in  temperature  of  the  liquid  the  number 
of  calories,  or  "combustion  equivalent,"  is  calculated.  In  the 


402 


PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 


case  of  proteins  oxidation  is  not  so  complete  within  the  body 
as  without,  urea,  the  chief  product,  not  being  completely 
burned.  The  combustion  equivalent  of  urea  is  2.523  calories. 
One  gin.  of  proteid  yields  about  1/3  gm.  urea;  hence,  to  get 
the  average  available  energy  of  protein  food  to  the  body  841 
calories  must  be  deducted  from  the  theoretic  equivalent:  thus, 
5.778  —  0.841  =  4.937.  The  equivalents  of  fats  and  carbohy- 
drates are,  respectively,  9.312  and  4.116  calories. 

An  acid  reaction  quickly  destroys  the  irritability  of  bio- 


en  \ENT 


Fig.  50.— Reichert's  Water-calorimeter. 

plasm.     The  inorganic  salts  of  the  body-fluids  neutralize  the 
acids  formed  in  metabolism. 

During  starvation  the  circulating  proteins  are  first  drawn 
upon,  then  the  body-fat  (perhaps  reconverted  into  dextrose), 
and  then  the  muscles,  to  nourish  other  tissues  and  maintain 
body-temperature.  Hence  the  loss  of  protein  is  greatest  during 
the  first  day  or  two  of  fasting.  A  well-nourished  adult,  drink- 
ing an  abundance  of  water,  can  keep  alive  without  food  for  six 
weeks  or  more,  while  a  delicate  child  would  succumb  within  a 
week.  Death  from  starvation  supervenes  with  coma  and  delir- 


RESPIRATION.  403 

ium  after  the  body-weight  is  reduced  from  one-third  to  one- 
half. 

The  elective  affinity  of  the  ingredients  of  glandular  cells 
for  certain  waste-products  in  the  blood,  as  of  the  kidneys  for 
urea,  is  a  chemic  problem  still  unsolved.  The  formation  of 
true  secretions  by  gland-cells,  as  HC1  and  pepsin,  must  depend, 
in  general,  upon  a  specialized  protoplasmic  metabolism.  These 
cells  in  giving  forth  their  secretion  products  seem  themselves 
to  break  down  and  dissolve.  The  possible  uses  of  the  waste- 
products  of  one  tissue  for  the  needs  of  another  is  exemplified 
by  the  burning  of  sarcolactic  acid  to  form  uric  acid. 

The  interstitial  circulation  of  lymph,  from  which  the  fac- 
tors of  metabolism  are  obtained  and  by  which  the  waste-prod- 
ucts are  taken  up  to  be  excreted,  is  maintained  normally  by  a 
delicately  adjusted  osmotic  and  diffusion  process.  The  dif- 
fusion of  soluble  constituents  takes  place  continuously  from 
the  side  of  greater  concentration  to  that  of  less  (out  of  or  into 
the  capillaries),  and  is  not  dependent  on  the  osmotic  water- 
current;  lymph  may  become  more  concentrated  even  than 
plasma.  The  blood-capillaries  are  more  permeable  to  urea  than 
to  salt  or  sugar:  a  fact  which  favors  the  excretion  of  the  former 
compound.  The  osmotic  pressure  of  serum  proteins  is  about 
30  mm.  in  the  capillaries  (only  10  mm.  in  the  lymph-vessels): 
a  constant  factor  in  promoting  resorption  from  the  tissues. 
Lymphagogs,  such  as  sugar  and  neutral  salts,  increase  the 
osmotic  pressure  of  the  circulating  blood,  thereby  attracting 
water  from  the  lymph  and  tissues,  producing  hydremic  plethora, 
rise  of  capillary  pressure,  and  great  increase  in  transudation, 
and  hence  in  the  lymph-flow.  Intracapillary  blood-pressure  is 
ordinarily  30-50  mm.  Hg.  When  it  falls  below  20  mm.,  ab- 
sorption of  water  from  the  lymph-spaces  results. 

When  the  balance  is  broken  and  transudation  becomes 
excessive,  we  have  the  condition  of  dropsy,  ascites,  or  anasarca. 
Dropsic  states  are  relieved  by  a  dry  diet  and  by  diuresis,  both 
of  which  promote  low  blood-pressure  with  increased  osmosis 
into  the  capillaries. 

RESPIRATION. 

The  respiratory  changes  effected  in  the  blood  are  briefly 
a  gain  of  0  (8  per  cent.)  and  a  loss  of  C02  (7  per  cent.).  The 
latter  is  under  high  tension  through  the  acid  action  of  the  red 
corpuscles  and  serum-albumin  on  NaHC03;  about  5  per  cent, 
of  the  gas  is  in  simple  solution.  The  0  is  taken  up  at  once 
by  the  hemoglobin  (0.26  volume  per  cent,  free)  and  carried 


404  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

to  the  tissues,  where  0  tension  is  nil  and  C02  tension  high,  and 
hence  internal  respiration  takes  place  with  a  loss  of  0  and  a 
gain  of  C02.  The  0  is  probably  united  with  the  protoplasm  in 
a  somewhat  firmer  union  than  oxyhemoglobin.  The  minimal 
constant  of  dissociation  of  oxyhemoglobin  is  1/30  to  V10  atmos- 
phere. 

The  0  pressure  is  less  by  over  20  per  cent,  in  the  alveoli 
than  in  the  nares.  This  tension  of  0  in  alveolar  air  is  about 
22  mm.;  the  tension  of  0  in  arterial  blood  is  29.64  mm.;  in 
venous  blood,  22  mm.  The  alveolar  tension  of  C02  at  sea-level 
is  38  mm.;  in  venous  blood,  41  mm.;  in  arterial  blood,  21.28 
mm.  The  muscles  have  the  greatest  avidity  for  0  of  any  of  the 
tissues. 

The  volume  of  air  respired  at  each  respiratory  act  is  about 
500  c.c.,  equivalent  to  450  liters  per  hour  or  380  cubic  feet  per 
day.  Inspired  air  contains  nearly  21  per  cent.,  by  volume,  of 
0  and  0.04  volume  of  C02.  Expired  air  contains  16  volumes 
per  cent,  of  0  and  4.38  per  cent.,  by  volume,  of  C02.  The  tem- 
perature of  expired  air  is  raised  to  36.3°,  and  the  actual  volume 
of  air  is  diminished  2  to  2  */2  Per  cent.,  when  allowance  is  made 
for  the  expansion  (10  or  12  per  cent.)  caused  by  the  rise  in 
temperature. 

Expired  air  is  saturated  with  water  (20  to  40  gm.  per  hour) 
and  contains  traces  of  NH3  and  other  organic  effluvia,  which 
give  rise  to  the  bad  odor  of  ill-ventilated  sleeping-rooms. 

Cutaneous  respiration  in  man  is  of  minor  importance,  the 
ratio  with  pulmonary  respiration  of  0  absorbed  being  about  1 
to  100;  and  of  C02  eliminated,  1  to  200-500. 

Dyspnea  develops  when  inspired  air  contains  less  than  13 
volumes  per  cent,  of  0,  and  is  also  caused  by  excess  of  C02  in 
the  blood.  The  cyanosis  observed  in  asphyxia  from  deprivation 
of  air  is  due  to  the  nearly  complete  reduction  of  oxyhemoglobin. 
The  hemorrhages  and  other  symptoms  of  caisson  disease  are 
attributable  largely  to  the  sudden  escape  from  the  blood  of  air 
which  has  been  forced  in  under  high  pressure. 


POOD   AND   DIET. 

The  purpose  of  food  is  to  sustain  life;  to  produce  mus- 
cular, nervous,  and  glandular  energy  and  heat;  to  promote 
growth;  and  to  prevent  the  too  rapid  destruction  of  the  or- 
ganic constituents  of  the  body.  The  three  chief  classes  of  food 
are  proteins,  or  tissue-formers;  and  the  fuel  foods,  fats  and 
carbohydrates,  both  of  which  are  chiefly  producers  of  heat  and 


FOOD  AND  DIET.  405 

energy.  Proteins  are  also  the  source  of  the  digestive  fluids, 
and  regulate  oxidation  and  energy. 

One  gm.  of  protein  burned  outside  the  body  yields  5.778 
calories  or  1812  kilogrammeters;  1  gm.  of  fat,  9.312  calories  or 
3841  kilogrammeters;  1  gm.  of  glucose,  4.116  calories  or  1657 
kilogrammeters.  These  figures  are  the  same  practically  for 
combustion  within  the  body,  except  in  regard  to  proteins,  as 
already  explained.  The  human  body  utilizes  as  dynamic  energy 
a  little  over  half  of  the  potential  energy  of  the  food  ingested. 
A  steam-engine  can  utilize  only  one-eighth  of  the  potential 
energy  of  fuel. 

The  daily  quantity  of  calories  (heat,  energy,  and  tissue- 
repair)  required  to  keep  the  healthy  adult  human  machine  in 
good  working  order  has  been  reckoned  at  from  2400  to  6000 
(average,  3500),  much  more  being  needed  when  at  hard  mus- 
cular labor  than  when  at  rest.  Such  calculations  are  based 
mainly  on  examination  of  the  excreta.  Thus,  1  gm.  N  =  6  */4 
gm.  albumin  =  29.4  gm.  muscle  =  2.143  gm.  urea.  Again,  a 
man  weighing  150  pounds  gives  off  about  15  cubic  feet  of  C02 
in  24  hours,  equivalent  to  2400  foot-tons  of  energy.  Allowance 
must  also  be  made  for  the  heat  or  energy  required  to  keep  up 
the  body-temperature. 

It  is  possible  for  a  person  to  live  entirely  upon  proteins, 
but  not  upon  a  non-nitrogenous  diet  for  any  length  of  time. 
Nearly  all  foods  contain  more  or  less  proteins:  wheat,  14.6 
per  cent.;  barley,  12.8  per  cent.;  oats,  17  per  cent.  An  excess 
of  proteid  food  above  the  amount  needed  to  repair  tissue-waste 
is  burnt  up  into  urea  and  excreted  without  serving  any  useful 
end;  indeed,  on  the  contrary,  it  overtaxes  the  liver  and  the 
kidneys,  causing  functional  (lithemia)  or  organic  disease  of  these 
organs. 

Excess  of  carbohydrates  is  stored  up  as  adipose  tissue. 
Fatty  foods,  it  will  be  noted,  yield  much  more  heat  than  do 
proteins  or  carbohydrates;  hence  in  winter  and  in  cold  regions 
people  desire  and  require  more  fats. 

The  most  healthful  and  economic  diet  is  evidently  one  so 
balanced  as  to  nitrogenous  and  non-nitrogenous  foods  that 
there  is  no  excess  or  lack  of  either.  The  proper  proportion  of 
N  to  C  has  been  estimated  to  be  about  1  to  15.  Parke  states 
that  a  working  man  needs  2/3  oz.  N"  and  8  to  12  oz.  C  daily. 
Another  daily  diet  table  is  for  proteins  110. gm.  at  rest,  118 
gm.  at  moderate  labor,  145  gm.  at  severe  work;  fats,  50,  55, 
and  100  gm.,  respectively;  and  carbohydrates,  450,  460,  and 
500  gm.,  respectively.  Vaughan  states  that  such  requirements 
are  most  cheaply  fulfilled  by  a  diet  of  bread,  codfish,  lard,  pota- 


406  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

toes,  bacon,  beans,  milk,  sugar,  and  tea.  The  total  weight  of 
food  per  diem  for  an  average  adult  should  be  about  60  oz.  A 
slightly  alkaline  reaction  favors  gastric  secretion  and  digestion. 

The  proportion  of  N  to  C  in  proteins  is  about  2  to  7;  in 
albuminoids,  2  to  5  V2.  In  fats  there  is  about  1  H  to  7  C, 
with  not  enough  0  to  burn  all  of  the  H,  forming  water.  Carbo- 
hydrates have  just  enough  0  to  oxidize  the  H,  and  the  weight 
of  H  is  V6  or  1/7  that  of  C.  Organic  acids  have  more  than 
enough  0  to  burn  the  H. 

If  a  person  were  to  live  upon  lean  beef  alone  2  or  3  kgm. 
would  be  required  daily  to  get  enough  non-nitrogenous  ele- 
ments; and  of  potatoes  alone  (less  than  2  per  cent,  proteins), 
8  kgm.  would  be  needed  to  furnish  enough  N. 

Fats  and  carbohydrates  are  more  needed  by  the  young, 
who  seldom  get  fat  on  account  of  their  greater  activity.  Fats 
and  albuminoids  save  the  tissues  and  are  especially  indicated 
in  chronic  febrile  diseases,  such  as  pulmonary  tuberculosis. 

In  addition  to  the  three  classes  of  nutriment  above  men- 
tioned, water"  and  salts  are  very  necessary.  Of  the  former,  three 
pints  or  more  daily  should  be  drunk  by  the  average  adult  in 
addition  to  that  taken  in  solid  food  (50  to  60  per  cent.).  A 
lack  of  water  to  flush  the  sewers  of  the  body  leads  to  constipa- 
tion, malassimilation,  melancholy,  and  many  obscure  aches  and 
pains.  Water  is  best  taken  mostly  between  meals,  so  as  not  to 
dilute  unduly  the  digestive  juices.  A  glass  of  ice-water  taken 
at  a  meal  drives  the  blood  from  the  stomach  and  delays  diges- 
tion at  least  an  hour. 

Common  salt  is  the  essential  source  of  the  HC1  of  the 
gastric  juice,  and  since  functional  indigestion  consists  in  hypo- 
chlorhydria  in  three-fourths  of  all  cases,  many  dyspeptics  find 
much  relief  from  eating  largely  of  salted  meats,  salted  crackers, 
etc.  The  reason  why  man  and  the  herbivora  require  salt  added 
to  their  food  is  explained  by  Bunge  as  due  to  the  K  salts 
uniting  with  the  NaCI  of  the  blood  to  form  KC1,  of  which  the 
excess  now  passes  out  of  the  system,  causing  thereby  a  loss  of 
NaCl  as  well.  Eice  contains  no  K  salts,  and  rice-eating  races 
require  no  salt. 

Of  other  food-salts  the  phosphates  are  most  important, 
being  bone-,  brain-,  and  nerve-  formers.  Fish  is  richest  in 
phosphates,  particularly  salmon  (6  to  7  per  cent.).  Flake-barley 
contains  4.2  per  cent.;  oats,  3  per  cent.;  wheat,  1.6  per  cent. 
The  phosphates  are  just  under  the  hard,  siliceous  coat  and  on 
the  surface  of  the  kernel.  Butchers'  meat  contains  about  2 
per  cent,  of  phosphates;  ham,  4  Y2  per  cent.;  and  beans,  3 
per  cent. 


FOOD  AND  DIET.  407 


ANIMAL  FOODS. 

These  are  generally  more  rapidly  and  completely  digested 
than  vegetable  foods.  Human  milk  is  the  ideal  food  for  in- 
fants. Cows'  milk  lacks  C  as  a  sole  article  of  diet  for  adults. 
It  is  usually  quite  fattening,  partly  because  of  its  ready  ab- 
sorbability and  partly  because  of  the  lactose  in  it.  It  predis- 
poses to  constipation,  because  there  is  hardly  any  residue  left 
from  digestion.  The  "bilious"  effect  of  milk  is  obviated  by 
adding  30  grains  of  common  salt  to  each  pint,  and  by  eating 
fruits.  Whey  and  junket  are  delicate  dishes  for  the  sick  and 
convalescent,  and  buttermilk  is  often  tolerated  when  rich  milk 
is  ill  borne.  Condensed  milk  is  preserved  by  the  addition  of 
sugar,  and  while  it  fattens  infants  it  is  not  nearly  so  nourishing 
as  properly  diluted  fresh  dairy  milk.  The  milk  of  goats  and 
asses  is  said  to  more  nearly  resemble  human  milk  than  does  the 
milk  of  the  cow,  but  the  difference  is  too  slight  to  be  of  account. 
Kefir  is  three  times  as  rich  in  albumin  as  koumiss,  and  half  as 
rich  in  alcohol  and  lactic  acid.  Boiled  milk  requires  two  hours 
to  digest.  It  is  less  digestible  than  unboiled  milk,  but  curdles 
in  small  flocculi  instead  of  large  masses,  and  so  is  more  thor- 
oughly exposed  to  the  action  of  the  gastric  juice. 

Cheese  contains  up  to  27  per  cent,  of  proteins  (chiefly 
casein)  and  up  to  30  per  cent,  of  milk-fat,  with  about  5  per 
cent,  each  of  sugar  and  salt.  It  is  highly  nutritious,  but  some- 
what indigestible  unless  very  thoroughly  masticated.  The 
practice  of  keeping  cheese  until  it  has  been  "cured" — that  is, 
putrid  from  butyric  acid  fermentation  (Limburger,  Roquefort) 
— is  in  contravention  to  all  hygienic  principles. 

In  digestibility  the  meat  of  fish  ranks  first  (trout,  1 1/2 
hours),  that  of  birds  second  (turkey,  2  V2  hours),  mammals 
third  (roasted  beef,  3  hours;  mutton,  3  */4  hours;  veal,  4 
hours;  salt  beef,  4  1/4  hours;  roast  pork,  5  1/4  hours),  and 
reptiles  fourth.  The  flesh  of  young  animals  is  less  digestible 
than  that  of  older.  Meats  contain  from  25  to  50  per  cent,  of 
fats  and  proteins.  The  amount  of  water  varies  from  15  per 
cent,  in  dried  bacon  to  72  per  cent,  in  lean  beef  and  mutton. 
The  proteins  of  meat  are  more  completely  digested  than  those 
of  milk. 

The  rotting  of  game  until  it  is  "high"  aids  digestibility  by 
the  corrosive  action  of  sarcolactic  acid  on  the  sarcolemma,  but 
it  is  a  dangerous  practice.  Uncooked  meat  is  liable  to  give  rise 
to  trichiniasis  or  a  tape-worm.  The  brown  color  of  well-done 
roast  beef  is  due  to  hematin.  The  peculiar  odor  and  flavor  of 
meats  depend  largely  on  creatin  and  osmazome  (developed  by 


408  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

heating).  Creatin  is  the  chief  ingredient  of  meat-extracts, 
which  are  stimulating,  but  not  nourishing,  and  are  excellent 
media  for  typhoid  bacilli.  They  aid  the  system  to  digest  and 
utilize  gelatin. 

The  so-called  peptonized  or  predigested  foods,  such  as 
somatose,  consist  almost  entirely  of  albumoses,  and  serve  a 
useful  purpose  in  many  instances  of  malnutrition.  If  artificial 
proteolysis  is  carried  too  far,  the  products  become  bitter  from 
some  unknown  substance. 

Eggs  contain  egg-albumin  and  vitellin,  a  ferronuclein,  the 
common  fats  and  a  yellow  lutein  (lipochrome),  a  little  dextrose, 
lecithin,  cholesterin,  and  chlorid  and  phosphate  of  K  and  Ca. 
Eggs  are  savory  and  digestible  and  very  nutritious,  but  undergo 
putrefaction  readily,  often  causing  eructations  of  H2S  and 
H3P.  According  to  the  observations  of  Beaumont  on  St. 
Martin,  raw  eggs  are  digested  in  1 1/2  to  2  hours;  hard  boiled 
or  fried  in  3  1/2  hours. 

Keratin  is  altogether  indigestible.  Elastin  changes  to 
elastoses.  Collagen  is  converted  by  the  gastric  juice  into 
gelatin. 

Gelatin  is  easily  oxidized,  and  hence  is  a  tissue-saver, 
though  not  a  tissue  former.  It  is  particularly  useful  for  young 
children  and  invalids;  100  gm.  gelatin  —  36  gm.  albumin. 

Animal  fats  are  more  easily  digested  and  absorbed  than 
vegetable  fats.  Fats  promote  the  flow  of  bile  and  pancreatic 
juice,  but  if  in  excess  interfere  with  or  inhibit  the  gastric  se- 
cretion. 

VEGETABLE  FOODS. 

Bread  is  made  from  cereal  flour  and  water,  usually  leavened 
by  means  of  yeast.  Wheat  flour  contains  about  15  per  cent, 
of  water,  8  to  12  per  cent,  of  gluten,  and  60  to  70  per  cent, 
starch;  also  sugar,  dextrin,  fat,  and  salts.  The  protein  pirin- 
ciples  are  in  the  bran  or  cortic  portion.  White  bread  is,  how- 
ever, more  digestible  than  that  made  from  the  whole  wheat. 
Too  fresh  or  poorly  baked  bread  forms  a  putty-like,  glutinous 
mass  in  the  stomach,  on  which  the  gastric  juice  can  have  little 
effect.  Oats  are  especially  rich  in  fats  (5.14  per  cent.),  maize 
ranking  next  and  rice  lowest. 

Potatoes  contain  about  20  per  cent,  of  starch.  The  K 
salts  are  just  beneath  the  skin.  Eice  contains  75  per  cent,  of 
starch.  Carrots  possess  considerable  iron.  Beans,  pease,  and 
lentils  contain  about  25  per  cent,  of  protein  (legumin)  and  over 
50  per  cent,  of  starch.  These  legumes  and  garden  vegetables 
are  apt  to  ferment  in  the  bowels,  owing  to  the  large  proportion 


FOOD  AND  DIET.  409 

of  water  and  cellulose  they  contain.  For  the  same  reason  green 
vegetables  must  be  used  quickly  after  gathering. 

Nuts  are  rich  in  fat  (pea-nuts,  46  per  cent.)  and  are  hence 
very  nutritious,  but  must  be  well  masticated.  The  organic  acids 
of  ripe  fruits  exist  therein  chiefly  as  alkaline  salts.  Fruit-acids 
stimulate  digestion,  and  the  cellulose,  sugar,  and  water  of  fruits 
help  constipation,  for  which  purpose  they  are  best  taken  before 
breakfast.  Apples  contain  considerable  phosphates  and  are  di- 
gested in  1 1/2  hours. 

The  volatile  oils  and  oleoresins  of  condiments  increase  the 
flavor  of  foods  and  stimulate  absorption  and  the  flow  of  secre- 
tions, but  must  be  used  moderately,  lest  they  irritate  the  mu- 
cous membrane. 

Eice,  barley,  and  tapioca  remain  in  the  stomach  about  2 
hours;  legumes  and  potatoes,  2  1/2  hours;  white  bread,  3  hours; 
brown  bread,  4  hours.  The  stomach  should  be  empty  of  all 
food  in  6  hours  after  a  meal. 


COOKING. 

To  boil  or  stew  meat  properly  the  water  must  be  boiling 
when  the  meat  is  put  in,  then  be  reduced  in  a  few  minutes  to 
160°  or  170°  F.  and  kept  so  till  the  meat  is  tender:  that  is, 
the  tendons  and  fibrous  tissues  gelatinized.  In  this  way  the 
albumin  and  globulin  at  the  surface  coagulate,  preventing  loss 
of  juices.  The  reverse  process  should  be  followed  in  making 
broths;  the  addition  of  salt  helps  to  extract  myosin.  Vege- 
tables are  better  steamed  than  boiled,  in  order  to  retain  their 
special  virtues.  Digestion  of  carbohydrates  is  aided  chiefly  by 
hydration  of  starches. 

For  frying  purposes  the  oil  or  fat  should  be  boiling  when 
the  dough  is  put  in.  Otherwise  the  paste  becomes  saturated 
with  grease  and  very  difficult  of  digestion. 

Boasting  is  best  done  in  the  open  air,  where  the  meat  be- 
comes more  savory,  digestible,  and  nutritious.  Broiling,  or 
grilling,  and  baking  are  modes  of  roasting.  In  baking  bread 
the  glucose  produced  from  the  starch  of  the  flour  is  fermented 
by  yeast  into  alcohol  and  C02,  which  causes  the  dough  to  rise, 
and  on  heating  the  loaf  continues  to  expand  until  the  gluten 
is  coagulated  and  the  bread  sets  in  a  vesiculated  mass.  The 
alcohol  escapes  into  the  air.  The  crust  is  most  digestible,  being 
composed  mainly  of  dextrin.  Bread  becomes  sour  from  lactic 
and  butyric  acids  when  fermentation  is  allowed  to  go  too  far 
(alum  prevents).  A  loaf  of  bread  is  not  sterilized  throughout 
by  baking. 


410 


PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 


BEVERAGES. 

Dilute  alcoholic  liquors  increase  the  flow  of  gastric  juice 
and  are  rapidly  absorbed.  They  are  not  tissue-builders,  but 
tissue-savers,  as  shown  by  decrease  of  urea,  being  burned  in 
the  capillaries  into  C02  and  H20  to  the  extent  of  1 1/2  or  2 
oz.  daily;  1  gm.  alcohol  =  0.071  calorie.  Hence  they  are  of 
service  in  some  fevers.  Alcoholics  do  not,  however,  give  real 
strength.  When  used  continually  they  probably  combine  with 
the  nervous  tissue  of  the  brain,  interfering  with  proper  metab- 
olism and  predisposing  to  disease.  The  excessive  use  of  malt 


TABLE  OF  CALOKIFIC  VALUES.    (AFTER  FEANKLAND  AND  JURGENSEN. 
CALORIFIC  VALUE  OF  100  GRAMS  IN  CALORIES. 


Apples 66.00 

Arrowroot 391.20 

Asparagus 18.50 

Bean-soup       193.00 

Boiled  beef 209.00 

Broiled  beef 213  60 

Raw  beef        118.95 

Beef-fat       906.90 

Lean  beef       156.70 

Bread-crumbs 223.10 

Butter  814.00 

Buttermilk 41.56 

Cabbage      43.40 

Cakes          374.00 

Cane-sugar 334.80 

Carp         93.00 

Carrots 41.00 

Chicken-breast 106.40 

Cheshire  cheese 464.70 

Codliver-oil 910.70 

Cream 214.70 

Hard-boiled  egg 238.30 

Yelk  of  egg 342.30 


White  of  egg 67.10 

Flour       393.60 

Flounder 100.60 

Macaroni 352.60 

Mackerel 178.90 

Milk 66.20 

Skim-milk      39.61 

Oatmeal      400.40 

Omelet 236.70 

Pea-meal 393.60 

Potatoes      101.30 

Pigeon 99.70 

Green  pease 318.00 

Salmon  133.30 

Ground  rice 318.30 

Trout .        .    .  106.40 


Veal  cutlets  (raw)    .    . 
"         "       (broiled)  . 
Wheat  bread  .    . 

"      (toasted) 
Whiting 


.  142.45 
.  230.50 
.  281.00 
.  258.80 
.  90.40 
Zwieback .  357.80 


liquors  leads  to  the  putting  on  of  fat,  from  imperfect  oxidation 
and  elimination  chiefly. 

The  alkaloidal  beverages — tea,  coffee  (a  cup  contains  0.1 
gm.  of  caffein),  cocoa,  chocolate,  kola,  and  mate — are  nerve- 
stimulants  and  are  closely  related  to  uric  acid.  Hence  their 
continued  use  is  likely  to  excite  migraine  and  other  uricacidemic 
conditions.  Tea  and  coffee  should  always  be  prepared  by  a 
few  minutes'  infusion  with  nearly  boiling  water,  as  prolonged 
boiling  drives  off  the  aromatic  flavoring  oil  and  causes  the 
water  to  take  up  a  bitter  astringent,  tannin,  a  radical  opponent 
of  eupepsia.  In  addition  to  caffein  (0.8  per  cent.),  caffeotannic 


AUTOTOXEMIA.  411 

acid,  and  the  aromatic  oil,  coffee-berries  contain  fat,  legumin, 
sugar,  dextrin,  vegetable  acids,  and  mineral  salts.  On  roasting, 
the  sugar  is  changed  to  caramel  and  the  aroma  develops.  Tea 
contains  about  3  per  cent,  of  thein  and  13  per  cent,  of  tannin 
(more  in  green  than  black),  as  well  as  dextrin,  glucose,  and  a 
volatile  oil.  Cocoa  is  the  most  nourishing  of  these  drinks,  since 
it  contains  50  per  cent,  of  fat  and  12  per  cent,  of  proteins. 

Lemon-juice  contains  about  .30  grains  of  citric  acid  per 
fluidounce.  It  is  of  special  use  in  scurvy,  which  appears  to  be 
a  mineral-acid  intoxication  due  to  an  exclusive  diet  of  meats 
or  cereals. 


AUTOTOXEMIA. 

Autointoxication,  or  poisoning  from  within  the  body,  is 
of  great  practical  importance  in  the  causation  of  various  dis- 
eased conditions.  The  agents  giving  rise  to  autointoxication 
may  be  either  pathologic  chemic  compounds  or  physiologic 
products  in  excess  of  normal  limits.  The  general  rule  is  that 
the  waste-products  of  any  organism  are  deleterious  to  it  and 
may  cause  death,  sometimes  suddenly,  when  reabsorbed  in  suffi- 
cient amount. 

The  toxic  endogenous  substances  giving  rise  to  autotoxemia 
include  the  fatty  acids  (beta-oxybutyric  causes  diabetic  coma), 
aromatic  phenols  (intestinal  autointoxication),  tyrosin  (hepatic 
insufficiency),  purin  bases  (uricacidemia,  migraine,  and  gout; 
guanin  from  cancerous  degeneration  causes  coma),  diamins 
(putrescin  and  cadaverin  in  gangrene  and  carcinoma);  mucin  in 
myxedema;  neurin  in  Addison's  disease;  the  amins  (especially 
trimethylamin),  aceton,  special  alkaloids,  and  leucomains,  and 
the  toxins  generated  by  the  colon  bacillus,  which  is  a  constant 
habitant  of  the  bowel. 

The  etiologic  classification  of  Albu  is  as  follows:  Arrest  of 
organic  function  (myxedema,  pancreatic  diabetes,  Addison's 
disease,  acute  yellow  atrophy);  anomalies  of  general  metab- 
olism (gout,  oxaluria,  diabetes);  retention  of  physiologic  meta- 
bolic products  (uremia  or  potassemia,  eclampsia,  cholemia,  as- 
phyxia, extensive  burns);  overproduction  of  physiologic  and 
pathologic  products  (overwork,  diacetemia,  ammonemia,  cysti- 
nuria,  etc.);  decomposition  of  food-substances  arising  from 
maldigestion.  The  last  class  is  most  common,  and  is  usually 
accompanied  by  constipation,  indicanuria,  and  neurasthenic 
symptoms. 

Lithemia,  or  biliousness,  is,  generally  speaking,  the  mani- 
festation of  an  overworked  and  long-suffering  liver.  The  thy- 


412  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

roid  gland  is  involved  in  myxedema,  cretinism,,  cachexia  stru- 
mipriva,  and  possibly  exophthalmic  goiter;  the  pancreas  in  dia- 
betes mellitus;  the  liver  in  jaundice  or  cholemia,  lithemia, 
acute  yellow  atrophy,  and  icterus  gravis;  the  kidneys  in  uremia 
and  eclampsia;  the  adrenals  in  Addison's  disease;  the  lungs  in 
C02  poisoning  from,  interference  with  respiration;  the  gastro- 
intestinal tract  in  the  depressed  nervous  conditions  accompany- 
ing constipation,  indicanuria,  and  oxaluria;  the  skin  in  the 
phenomena  following  severe  burns  of  large  surfaces;  and  the 
pituitary  gland  perhaps  in  acromegaly. 

The  manifestations  of  autotoxemia  in  any  given  case  are 
usually  manifold,  and  not  confined  to  one  organ.  Nervous 
symptoms  are  the  most  frequent,  and  comprise  headache,  ver- 
tigo, syncope,  irritability,  insomnia,  hypochondria,  stupor,  coma, 
delirium,  spasms  or  convulsions,  paralysis,  melancholia,  and 
mania;  polymyositis  has  been  noted  in  a  few  instances.  Com- 
mon cardiac  symptoms  are  tachycardia,  bradycardia,  and  arhyth- 
mia.  The  breathing  may  be  stertorous  or  of  the  Cheyne-Stokes 
type.  The  temperature  may  be  pyretic  or  subnormal,  usually 
the  first.  Digestive  symptoms  include  anorexia,  nausea,  vomit- 
ing, eructations,  diarrhea,  constipation,  and  colic.  Toxemic 
disturbances  of  the  urinary  tract  are  manifested  by  albuminuria, 
hematuria,  hemoglobinuria,  choluria,  acetonuria,  diaceturia, 
and  oxaluria.  The  skin  may  be  anemic,  jaundiced,  or  bronzed, 
and  not  seldom  shows  an  erythematous  eruption.  Cachexias 
are  frequent,  particularly  those  of  cancer,  diabetes,  chlorosis, 
leukemia,  pernicious  anemia,  and  the  uric-acid  diathesis.  In- 
fantile rickets,  purpura,  scurvy,  and  pernicious  anemia  are  often 
of  autotoxemic  origin.  Chlorosis  is  said  to  be  a  sequel  of 
copremia. 

INFECTION  AND  IMMUNITY. 

Most  infectious  diseases  are  known  to  be  caused  by  the 
presence  in  the  body  of  specific  bacteria,  which  generate  soluble 
poisonous  bases,  or  toxins,  that  act  as  the  direct  cause  of 
all  the  morbid  symptoms.  The  term  intoxication  is  applied 
when  infectious  microbes  remain  localized  and  only  their  toxic 
products  enter  the  system.  A  certain  bacterium  may  produce 
one  or  more  toxins.  Thus,  the  tetanus  bacillus  is  responsible 
for  four  distinct  toxins:  tetanin,  tetanospasmin,  tetanolysin, 
and  one  unnamed.  The  relative  toxicity  of  toxins  in  general 
is  enormous;  the  diphtheritic  toxin  can  produce  lethal  results 
in  a  living  being  20,000,000  times  its  own  weight.  Tetanus 
toxin  is  300  times  as  toxic  as  strychnin.  The  incubation  period 
of  an  infectious  disease  is  the  period  during  which  sufficient 


INFECTION  AND  IMMUNITY.  413 

toxins  are  being  formed  to  produce  an  appreciable  constitu- 
tional effect. 

When  diphtheria  toxin  is  injected  into  a  susceptible  ani- 
mal,, as  the  horse,  in  gradually  increasing  doses,  the  said  animal 
acquires  a  marked  tolerance  to  the  poison,  so  that  an  amount 
can  finally  be  injected  which  at  first  would  have  proved  quickly 
fatal.  The  serum  of  the  animal's  blood  also  acquires  the  prop- 
erty of  protecting  other  animals  against  diphtheria  when  in- 
jected subcutaneously  in  sufficient  dose.  Such  serum  when 
concentrated  is  known  as  antitoxin,  and  is  standardized  by 
physiologic  tests  against  a  given  quantity  of  toxin:  both  being 
injected  at  the  same  time  into  guinea-pigs.  A  normal  anti- 
toxic unit  is  equivalent  to  1  c.c.  of  normal  serum,  and  will 
counteract  100  doses  of  toxin  fatal  to  the  guinea-pig. 

According  to  the  Ehrlich  theory  of  immunity,  the  presence 
of  toxins  in  the  blood  stimulates  the  protoplasm  of  the  leuco- 
cytes and  the  fixed  tissues  to  an  intramolecular  migration  of 
atoms  to  a  more  stable  position.  In  this  change  are  thrown 
out  certain  side-chains,  or  receptors,  which  have  a  particular 
destructive  affinity  for  the  given  toxin  and  combine  with  and 
neutralize  it.  The  molecules  are  not  broken  apart  if  the  stimu- 
lation is  slight,  but  protoplasmic  resistance  to  the  toxins  is  in- 
creased, as  exemplified  by  vaccination.  Under  increased  stim- 
ulus by  the  toxins  myriads  of  these  side-chains  are  liberated 
into  the  serum,  giving  it  antitoxic  properties,  and  constituting 
the  more  or  less  perfect  active  artificial  immunity  observed  after 
one  attack  of  a  contagious  disease.  It  is  claimed  that  the 
amount  of  antitoxin  set  free  can  be  augmented  by  the  admin- 
istration of  agents  (pilocarpin)  which  stimulate  cell-activity. 
Antitoxins  may  also  be  formed  by  the  stimulating  action  of 
non-bacterial  proteins  (ricin,  abrin). 

If,  on  the  other  hand,  as  in  malignant  cases,  the  toxin  is 
overwhelming  in  force  and  amount,  reaction  is  paralyzed,  no 
side-chains  are  evolved,  and  the  patient  quickly  succumbs. 
Passive  immunity  is  that  conferred  by  the  injection  of  anti- 
toxins (diphtheria,  tetanus,  antistreptococcic,  etc.),  and  is  of 
much  snorter  duration  than  active  immunity,  since  it  is  not 
re-enforced  by  fresh  supplies  from  the  cells  and  is  gradually 
eliminated. 

The  natural  immunity  which  some  persons  and  animals 
exhibit  toward  certain  infections  is  explained  on  the  entire 
absence  of  receptor  formation  and  hence  of  combination  with 
the  toxins;  in  other  words,  the  toxins  do  no  harm  because  the 
protoplasm  is  not  affected  by  them.  It  is  further  possible  for 
a  subject  to  be  susceptible  to  the  toxins  of  a  disease  when 


414  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

directly  injected  and  yet  not  amenable  to  ordinary  inoculation 
by  the  germs  of  the  disease,  since  the  latter  may  not  thrive  in 
their  environment  with  sufficient  vigor  to  produce  toxins  in 
any  quantity. 

Snake-venoms  belong  to  the  class  of  toxalbumins,  and  the 
protective  and  curative  action  of  antivenene  is  probably  a  bio- 
chemic  reaction  analogous  to  that  of  antitoxins.  It  is  a  curious 
fact  that  venom  when  taken  by  the  stomach  protects  against 
snake-bites,  and  the  same  is  true  of  antivenene,  but  antitoxins 
are  ordinarily  best  given  hypodermically.  Vaughan  believes 
that  toxins  and  antitoxins  are  nucleins,  neutralizing  each  other 
chemically. 

Chemically  speaking,  tubercle  bacilli  consist  of  protoplasm 
inclosed  within  a  waxy  capsule.  The  toxic  products  of  the  life- 
processes  of  tubercle  bacilli  include  a  systemic  poison,  a  fever- 
producing  agent,  and  a  necrotic.  Tuberculin  (the  old  T.  0., 
not  T.  R.)  is  a  4-  to  7-per-cent.  glycerin  extract  prepared  from 
old,  concentrated  culture-media  of  tubercle  bacilli.  It  contains 
salts,  pepton,  albumose,  and  other  undefined  proteins,  one  of 
which  is  a  fever-producing  toxin,  and  is  used  for  diagnostic  pur- 
poses in  the  dose  of  1/2  or  1  mg. 

HEMOLYSINS. 

It  has  been  discovered  that  the  serum  of  one  animal  in- 
jected with  the  blood  of  another  becomes  toxic  for  the  animal 
whose  blood  was  injected,  agglutinating  and  dissolving  the  red 
corpuscles  of  the  blood.  Such  toxic  substances,  when  produced 
by  the  injection  of  heterologous  blood,  are  termed  heterolysins. 
When  the  injections  are  in  the  same  species  isolysins  are 
formed.  Autolysins  have  so  far  not  been  produced.  The  serum 
of  many  animals  is  naturally  cytotoxic  and  hemolytic,  and  the 
same  is  true  of  snake-venoms.  Repeated  injections  in  increas- 
ing dosage  lead  to  the  development  of  an  antitoxic  resistance 
to  the  poisons.  Certain  toxins  (tetanolysin)  contain  two  sets 
of  molecules,  one  binding  the  antitoxins  (haptophorous)  and 
one  producing  hemolysis  (toxophorous).  Leucocytolysins  are 
similar  in  action  to  hemolysins,  dissolving  the  white  blood-cells, 
however,  without  previous  agglutination.  Various  theories  of 
cytolysis  have  been  proposed.  One  is  that  in  immune  serums 
there  are  two  distinct  substances,  namely:  the  specific  immune 
or  anti-  body  (globulolytic  and  bacteriolytic),  which  is  not  de- 
stroyed by  heat;  and  the  non-specific  alexin  or  complement, 
which  is  destroyed  at  50°  to  60°  and  which  exists  preformed 
in  all  blood.  In  hemolysis  it  is  claimed  that  the  anti-body  is 


INFECTION  AND  IMMUNITY.  415 

bound  by  the  stroma  of  the  red  corpuscles  or  perhaps  links  the 
alexin  to  the  cells.  Another  explanation  of  hemolysis  by  im- 
mune serums  is  through  a  sudden  disturbance  of  osmotic  equi- 
librium. 

Anticytotoxins  is  the  term  applied  to  substances  that  neu- 
tralize hemolytic  serums.  They  are  produced,  in  a  similar  way 
to  antitoxins,  by  injecting  hemolytic  serums  in  increasing  doses 
into  susceptible  animals.  They  seem  to  include  both  anti- 
alexins  and  anti-immune  bodies. 

Various  other  toxic  and  antitoxic  substances — such  as  epi- 
theliolysin,  spermotoxin,  and  nephrolytic  serum — are  developed 
by  the  natural  resistance  of  the  cells  to  outside  influences.  It 
is  possible  that  in  some  cases  sterility  depends  on  the  presence 
of  spermotoxic  substances  in  woman's  blood. 


BACTERIOLYSINS. 

Bacteriolysins  are  complex  substances  composed  of  a  pep- 
tonizing  ferment  and  a  bacterial  derivative.  They  have  a  di- 
gestive and  antibacterial  action,  but  no  effect  on  toxins,  which 
they  set  free,  sometimes  aggravating  the  condition. 

Destruction  of  bacteria  may  be  due  to  plasmolysis  or  plas- 
moptysis  (spewing  out  of  cell-contents),  depending  on  osmotic 
disturbances.  Thus  the  diplococcoid  form  of  colon  bacilli  said 
to  be  found  in  cirrhotic  livers  and  the  accompanying  ascitic 
fluid  are  perhaps  degenerating  forms  due  to  plasmolysis.  These 
dead  bacilli  and  bacillary  fragments  tend  to  take  up  iron,  form- 
ing pigment-granules.  Bacteriolysins  may  further  be  produced 
by  the  digestion  of  bacteria  with  peptonizing  ferments.  These 
lysins  are  pptd.  by  acetic  acid  and  dissolve  again  in  alkaline 
water. 

AGGLUTINATION. 

This  curious  property,  forming  the  basis  of  the  Widal  test 
for  typhoid  fever,  appears  to  be  due  to  the  action  of  agglutinins 
of  unknown  origin,  so  changing  the  bacterial  membrane  as  to 
render  it  sticky.  The  agglutinating  property  of  serum  is  not 
destroyed  by  heating  to  180°.  Its  homologous  nature  is  not 
characteristic,  since  typhoid  bacilli  are  clumped  by  diphtheria 
antitoxin. 

The  agglutination  of  blood-corpuscles  in  coagulation  is 
most  marked  in  pneumonia,  rheumatism,  erysipelas,  and  ty- 
phoid. Owing  to  the  firmness  of  the  clot  in  these  cases,  the 
buffy  coat  is  unusually  distinct. 


416  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 


QUESTIONS  ON  PHYSIOLOGIC  AND  PATHOLOGIC  CHEMISTRY. 

1.  Why  is  saliva  frothy  and  viscid? 

2.  What  is  the  color  of  the  stools  in  jaundice? 

3.  How  detect  starch  in  feces?     Fat?     Mucus?     Casein? 

4.  Why  does  the  sweat  often  smell  sour  in  summer? 

5.  How  does  taking  HC1  diminish  the  amount  of  NH3  in  the  urine? 

6.  What  effect  does  muscular  exertion  have  on  the  alkalinity  of 
the  blood? 

7.  How  does    (NH4)2C2O4,  added  to  freshly  drawn  blood,  prevent, 
its  coagulation? 

8.  Why  does  a  sip  of  vinegar  cause  pain  in  mumps? 

9.  What  causes  the  film  on  the  surface  of  saliva  on  standing? 

10.  How  does  deficient  motility  interfere  with  stomach-digestion?" 

11.  Why  not  feed  a  young  baby  crackers? 

12.  Why  do  we  need  to  add  salt  to  our  food? 

13.  How  detect  with  certainty  the  presence  of  saliva  in  the  stomach- 
contents  ? 

14.  Why  is  whole-wheat  bread  more  nutritious  and  less  digestible 
than  white  bread? 

15.  Why   are   sterilized   milk   and   artificial   infant-foods  likely   to- 
produce  rickets  and  scurvy? 

16.  Why  is  it  best  to  boil  potatoes  in  their  skins? 

17.  What  kind  of  diet  is  best  for  hypochlorhydria? 

18.  Why  is  toast  more  digestible  than  untoasted  bread? 

19.  Why  must  the  blood  be  saline?     Alkaline? 

20.  What  chemic  effects  have  fruits  on  blood  and  urine? 

21.  Explain  the  chemistry  of  infantile  colic. 

22.  What  chemic  compounds  are  present  in  hair? 

23.  Why  do  the  nursing  mother's  teeth  often  decay  rapidly? 

24.  Write  formulas  for  xanthin,  theobromin,  caffein    (them),  and 
uric  acid. 

25.  Gall-stones  are  most  frequent  in  fat,  elderly  women.     Why? 

26.  To  reduce  obesity  what  kinds  of  food  should  be  avoided? 

27.  Why  is  fracture  in  children  often  of  the  "green  stick"  type? 

28.  What  chemic  changes  accompany  muscular  contractions? 

29.  What  is  the  chemistry  of  atheroma? 

30.  What  is  the  difference  in  composition  between  blood-  serum  and 
plasma  ? 

31.  What  element  is  indicated  medicinally  in  anemic  conditions? 

32.  What  is  the  color  of  a  person's  lips  poisoned  by  "blowing  out 
the  gas"? 

33.  Explain  the  symptoms  of  "heart-burn"  and  "water-brash." 

34.  Why  do  milk  and  other  proteid  foods  give  relief  in  hyperchlor- 
hydria  ? 

35.  State  the  chemic  distinctions  between  gastric  ulcer  and  gastric 
cancer. 

36.  What  hydrocarbon  is  found  in  the  body?    What  alcohol?    What 
ethers  ? 

37.  Compare  the  composition  of  human  and  bovine  milk. 

38.  What  are  the  chemic  differences  between  whey  and  butter-milk  ? 

39.  How  does  chyle  differ  from  lymph? 

40.  Give    some   chemic    reasons    for   the    symptoms    of    Addison's 
disease. 

41.  On  what  various  factors  does  diabetes  mellitus  depend? 


QUESTIONS.  417 

42.  How  distinguish  with  certainty  blood  in  the  stools  from  other 
coloring  matter? 

43.  Why  is  yellow  sputum  usually  more  liquid  than  white? 

44.  What  are  the  chief  distinctions  between  exudates  and  transu- 
dates? 

45.  How  do  potatoes  cure  scurvy? 

46.  If  1  gm.  urea  =  3  gm.  albumin,  how  much  protein  food  does 
a  laboring  man  weighing  140  pounds  require  daily? 

47.  What  advantages  have  cheese  and  pulses  over  meats  in  uric- 
acid  cases? 

48.  Name  ten  foods  especially  good  for  students,  and  give  reasons. 

49.  Define  internal  respiration. 

50.  What  substances  act  as  fuel  foods? 

51.  What  is  the  office,  chemically  speaking,  of  digestion? 

52.  Why   is   it   sometimes    advisable   to   prescribe   medicines    with 
ginger,  capsicum,  nutmeg,  and  other  spices? 

53.  Explain  from  the  physic  standpoint  the  removal  of  dropsies  by 
diuretics. 

54.  How  may  an  attack  of  uremia  be  pptd.  by  the  free  use  of  digi- 
talis after  tapping  an  ascites? 

55.  Distinguish  between  active  immunity,  passive  immunity,  vac- 
cination, and  natural  immunity. 

56.  W7hy  do  fats  generate  more  heat  in  the  body  than  carbohy- 
drates or  proteins? 

57.  Why  is  the  lowest  daily  range  of  normal  body-temperature  in 
the  early  morning? 

58.  Make  out  a  diet-table  for  3500  calories,  using  roast  beef,  wheat 
bread,  potatoes,  milk,  and  butter. 

59.  Why  should  diphtheria  antitoxin  be  given  as  early  as  possible? 

60.  How  does  the  addition  of  borax  or  Na2CO3  delay  the  souring  of 
milk? 

61.  Why  do  infants  become  anemic  when  limited  too  long  to  a  milk 
diet? 

27 


CLINIC  CHEMISTRY. 


GASTRIC     JUICE. 

FOE  clinic  purposes  the  stomach-contents  are  usually 
drawn  with  the  soft  stomach-tube  an  hour  after  taking  Ewald's 
test-breakfast.  This  consists  of  a  one-ounce  dry  roll  or  two 
pieces  of  toast  without  butter,  and  2/3  Pint  (500  c.c.  better)  of 
warm  water  or  weak  tea  without  milk  or  sugar.  The  double 
test-meal  of  Hemmeter  consists  of  a  full  meal  at  8  A.M.;  Ewald's 
test-meal  at  12  M.;  withdrawal  of  stomach-contents  and  exami- 
nation at  1  P.M.  Disappearance  of  the  entire  breakfast  points 
to  normal  digestion;  absence  of  all  proteids,  with  presence  of 
considerable  carbohydrates  =  hyperchlorhydria;  absence  of  all 
carbohydrates,  with  presence  of  some  beef  and  egg  =  hypo- 
chlorhydria  or  anacidity;  presence  of  entire  meal,  with  the  milk 
perhaps  all  uncurdled  =  achlorhydria  and  absence  of  ferments 
and  glandular  atrophy. 

The  quantity  of  gastric  juice  obtained  in  this  way  is  nor- 
mally about  40  c.c.;  more  than  60  c.c.  or  less  than  20  c.c.  is 
pathologic.  The  former  condition  points  to  dilation  and  motor 
insufficiency;  the  latter,  to  too  rapid  emptying  of  the  viscus. 
The  liquid  should  be  filtered  at  once  and  examined  as  soon  as 
possible. 

The  reaction  is  tested  with  litmus-paper,  and  is  normally 
frankly  acid.  The  presence  of  free  acids  is  shown  by  congo-red 
paper,  which  turns  deep  blue  with  1  part  in  50,000  of  mineral 
acid;  violet,  with  organic  acids.  Tropeolin  00  in  aqueous  solu- 
tion is  a  dark  yellow-red  or  brown  fluid,  changed  to  pink  by 
1  to  4000  of  free  HC1,  giving  a  bluish  residue  on  drying;  to  a 
straw  color  by  acid  salts.  Benzopurpurin  (6  B)  paper  is  turned 
an  intense  dark  brown  by  mineral  acids.  A  1  to  2000  aqueous 
methyl-violet  solution  added  to  the  specimen  yields  a  copper- 
blue  color  with  HC1;  a  violet-blue  with  organic  acids. 

Free  HC1  can  also  be  shown  by  the  addition  of  3  or  4 
drops  of  a  5-per-cent.  alcoholic  solution  of  dimethyl-amido- 
azobenzol,  which  gives  a  pink  color  if  this  acid  is  present  in  the 
free  state,  while  a  yellow  color  indicates  its  absence.  Giinz- 
burg's  reagent  is  prepared  by  dissolving  1  gm.  vanillin  and  2 
gm.  phloroglucin  in  100  c.c.  of  alcohol.  The  solution  to  be 
tested  is  placed  in  an  evaporating  dish,  2  or  3  drops  of  the 
(418) 


GASTRIC  JUICE.  419 

reagent  added,  and  the  mixture  evaporated  to  dryness  just 
below  the  b.p.  on  the  water-bath  or  over  a  small  flame.  A 
purple  or  pink-red  color  shows  free  HCL  Boas's  reagent  is 
prepared  by  dissolving  3  gm.  of  cane-sugar,  10  gm.  of  resorcin, 
and  3  c.c.  of  alcohol  in  100  c.c.  of  distilled  water.  To  the 
specimen  in  a  porcelain  dish  add  2  or  3  drops  of  the  reagent 
and  evaporate  as  above,  getting  with  free  HC1  a  vermilion  line 
at  the  edge  of  the  dried  fluid,  fading  to  reddish  brown  on 
cooling. 

Experiment. — Make  a  0.25-per-cent.,  a  0.05-per-cent.,  and  a  0.01- 
per-cent.  solution  of  HC1.  Perform  each  of  the  three  tests  described 
above  with  1  c.c.  of  each  of  these  three  solutions,  and  determine  which 
test  is  most  delicate. 

Uffelmann's  reagent  for  lactic  acid  is  prepared  by  adding 
a  drop  of  dilute  neutral  Fe2Cl6  to  10  c.c.  of  2.5-per-cent.  car- 
bolic acid  solution.  The  resulting  amethyst  color  is  discharged 
by  mineral  acids,  but  lactic  acid  changes  it  to  a  straw  color 
(butyric  brownish),  best  noted  by  comparing  with  another  tube 
containing  the  same  amount  of  iron  in  the  same  volume  of 
water.  The  reaction  is  interfered  with  by  much  free  HC1  and 
by  the  presence  of  cane-sugar  or  alcohol.  To  make  the  test 
positive  the  lactic  acid  must  be  isolated  by  extracting  several 
times  with  ether,  which  is  distilled  off  and  the  residue  dissolved 
in  water  for  testing. 

Test  for  Lactic  Acid  in  the  Gastric  Juice  (J.  P.  Arnold). — Solu- 
tion 1  =  0.2  c.c.  of  saturated  alcoholic  solution  of  gentian  violet  in  500 
c.c.  distilled  water.  Solution  2  =  5  c.c.  of  solution  of  ferric  chlorid  (U. 
S.  P.)  in  20  c.c.  of  distilled  water.  In  a  small  porcelain  capsule  mix  1 
c.c.  of  first  solution  and  1  m.  of  second,,  forming  a  bluish-violet  liquid. 
To  this  liquid  add  drop  by  drop  the  filtered  gastric  contents,  when  if 
lactic  acid  is  present  the  color  changes  to  green  or  greenish  yellow.  The 
reaction  is  distinct  with  1  drop  of  1  to  5000  solution  of  the  acid. 

Acetic  and  butyric  acids  are  recognized  by  their  distinctive 
odors.  Acetic  acid  also  gives  a  red  ppt.  with  dilute  Fe2Cl6; 
butyric,  a  tawny  red. 

Alcohol,  rarely  present  from  yeast-fermentation,  is  de- 
tected by  its  odor  or  by  the  iodoform  test. 

Test  for  Pepsin. — To  10  c.c.  of  the  gastric  juice  add  a  flake  of  co- 
agulated white  of  egg:  best  prepared  by  gradually  pouring  a  dilute 
solution  of  egg-albumin,  with  constant  stirring,  into  boiling  water.  Set 
aside  at  40°  for  2  or  3  hours;  if  not  dissolved  *n  this  time,  leave  over 
night  at  same  temperature.  If  free  HC1  is  absent  add  an  equal  volume 
of  0.5  per  cent.  HC1  before  putting  in  the  albumin.  A  failure  to  dissolve 
and  to  form  albumoses  (recognized  by  biuret  test)  indicates  the  absence 
of  pepsin.  A  few  shreds  of  washed  fibrin  should  dissolve  in  Y2  to  1  hour; 
the  disk  of  egg-albumin  in  10  or  12  hours  at  the  latest. 


420  CLINIC  CHEMISTRY. 

Test  for  Rennin. — Neutralize  5  c.c.  of  filtered  gastric  juice  with 
decinormal  alkali  solution,  and  an  equal  volume  of  carefully  neutralized 
milk,  and  keep  at  body-temperature.  Coagulation  should  take  place  in 
10  or  15  minutes  if  chymosin  is  present.  As  a  matter  of  fact,  the  gastric 
ferments  are  practically  always  present  when  there  is  free  HC1  in  the 
gastric  juice. 

The  Oppler-Boas  bacilli  are  unusually  long,  non-motile, 
club-shaped  bacilli,  present  in  large  numbers  in  gastric  cancer. 
To  detect  them  dry  and  fix  a  drop  of  the  stomach-contents  on 
a  cover-glass  and  place  for  3  minutes  in  very  dilute  gentian- 
violet  solution,  washing  out  in  water  and  mounting  in  Canada 
balsam.  Yeast-cells  and  sarcinaB  are  usually  found  in  fermenta- 
tive conditions. 


PRACTICAL  QUANTITATIVE  ANALYSIS  OF 
GASTRIC  JUICE. 

In  Toepfer's  method  four  reagents  are  required:  1.  Deci- 
normal NaHO.  2.  A  1-per-cent.  alcoholic  solution  of  phenol- 
phthalein,  to  indicate  total  acidity.  3.  A  1-per-cent.  aqueous 
solution  of  sodium-alizarin  sulphonate,  to  indicate  all  acids 
except  loosely  combined  HC1.  4.  A  0.5-per-cent.  alcoholic  solu- 
tion of  dimethyl-amido-azobenzol,  to  indicate  free  HC1  only. 

Put  10  c.c.  of  filtered  gastric  juice  into  each  of  three  beak- 
ers. To  the  first  add  1  or  2  drops  of  phenol-phthalein;  then  run 
in  the  decinormal  solution  till  a  deep-red  color  is  produced  which 
no  longer  increases  in  intensity.  To  the  second  add  3  or  4 
drops  of  the  alizarin  solution,  and  titrate  with  the  decinormal 
alkali  till  the  first  pure  violet  color  is  reached.  To  the  third 
beaker  add  3  or  4  drops  of  dimethyl-amido-azobenzol,  and  if  a 
red  color  is  produced  run  in  the  decinormal  alkali  till  the  red 
just  disappears  and  the  fluid  becomes  yellow. 

The  number  of  c.c.  required  for  the  first  beaker  (a)  repre- 
sents the  total  acidity;  for  the  second  beaker  (1)),  all  acids 
except  loosely  combined  HC1.  Hence,  deducting  &  from  a  leaves 
the  combined  HC1.  The  number  of  c.c.  needed  to  change  the 
color  in  the  third  beaker  (c)  represents  free  HC1.  Hence,  de- 
ducting c  from  &  leaves  the  organic  acids:  chiefly  or  wholly 
lactic. 

The  amount  in  grams  of  each  of  these  five  findings,  reck- 
oned as  HC1,  is  obtained  by  multiplying  the  number  of  c.c. 
required  in  each  instance  by  the  factor  0.003637  (no.  of  c.c. 
of  lactic  acid  by  0.009);  or  the  percentage  (when  10  c.c.  of 
juice  are  used)  is  found  by  multiplying  by  0.03637. 


MILK.  421 

Quantitative  Test  for  Lactic  Acid  (Strauss). — A  separating  funnel 
graduated  to  5  c.e.  below  and  25  c.c.  above  is  filled  to  the  lower  mark 
with  gastric  juice,  and  ether  is  added  to  the  upper  mark.  The  funnel  is 
corked,  well  shaken,  allowed  to  stand  till  the  fluids  separate,  and  the 
liquids  allowed  to  run  out  to  the  lower  mark.  Distilled  water  is  now 
added  to  the  upper  mark,  and  the  mixture  treated  with  2  drops  of  a  1 
to  10  solution  of  tincture  of  chlorid  of  iron.  On  shaking  the  mixture  an 
intense-green  color  is  produced  if  lactic  acid  is  present  to  the  extent  of 
1  to  1000  or  more;  pale  green  if  between  0.5  and  1  per  1000. 

Test  for  Gastric  Absorption. — Let  the  patient  take  a  capsule  con- 
taining 5  grains  of  KI  along  with  100  c.c.  of  water.  The  salt  should  be 
found  in  the  saliva  within  15  minutes,  as  shown  by  means  of  starch-paper 
wet  with  saliva,  then  touched  with  a  drop  of  HNO2.  Free  I  is  liberated, 
giving  with  the  starch  a  blue  color. 

Test  for  Gastric  Motility. — 1.  The  oldest  and  most  reliable  method 
is  that  of  Leube,  which  consists  in  washing  out  the  stomach  6  to  7 
hours  after  a  full  meal  of  meat,  soup,  and  bread,  or  2  Y2  hours  after 
Ewald's  test-breakfast.  Any  residue  found  at  this  time  denotes  a  lack 
of  motor  power. 

2.  Let  patient  take   10  grains  of  salol  in  capsules.     The  salol  is 
broken  up  in  the  intestines  and  should  appear  in  40  to  75  minutes  in 
the  urine  as  salicyluric  acid,  as  proved  by  filter-paper  dipped  in  10-per- 
cent. Fe2Cl0  solution  giving  a  blue  spot  with  a  drop  of  the  urine.     If  the 
reaction  comes  later  than  the  time  mentioned  or  if  it  lasts  30  hours  or 
longer,  the  motile  power  is  deficient. 

3.  Another  method  (Klemperer's)  of  estimating  the  motor  function 
of  the  stomach  is  to  wash  the  viscus  thoroughly  and  then  pour  through 
the  tube  100  c.c.  of  olive-oil,  removing  what  remains  2  hours  later  by 
aspiration,  at  which  time  the  residue  should  not  exceed  20  to  40  c.c. 

The  presence  of  food  in  the  fasting  stomach  before  break- 
fast indicates  a  high  degree  of  submotility,  usually  accompanied 
by  gastric  dilation. 

The  form  and  location  of  the  stomach  is  determined  by 
palpation  and  percussion.  For  these  maneuvers  the  organ 
should  be  distended  with  C02,  generated  by  administering,  each 
in  250  c.c.  of  water,  a  teaspoonful  of  tartaric  acid  followed  by 
the  same  quantity  of  sodium  bicarbonate.  This  procedure  is 
also  useful  in  palpating  tumors. 


MILK. 

Mothers'  milk  taken  to  be  tested  should  be  either  a  spec- 
imen from  the  whole  breastful  or  a  sample  taken  about  mid- 
way in  nursing.  The  milk,  whether  human  or  bovine,  should 
be  well  mixed  by  shaking  before  the  quantitative  tests  are 
applied.  It  should  be  as  fresh  as  possible.  The  quantity  for 
each  test  is  best  measured  with  a  graduated  pipet. 

The  reaction  of  milk  is  ascertained  by  means  of  both  red 
and  blue  litmus-paper.  Its  color  and  consistence  should  be 


422  CLINIC  CHEMISTRY. 

carefully  noted.  The  whiter  and  more  opaque,  the  richer  the 
milk  is,  unless  adulterated. 

The  specific  gravity  may  he  determined  hy  means  of  a 
cylinder  and  a  correct  hydrometer  or  Quevenne's  lactodensime- 
ter,  or  more  accurately  with  the  picnometer  or  the  lactometer. 
This  latter  instrument  is  so  graded  that  0°  on  its  scale  repre- 
sents a  sp.  gr.  of  1, — that  of  water, — while  100°  is  equivalent 
to  a  sp.  gr.  of  1+029,  the  normal  minimum  of  good  milk,  and 
120°  to  1.034.  Genuine  cows'  milk  usually  ranges  from  105° 
to  120°.  Skim-milk  is  heavier.  Watered  milk  is  of  low  specific 
gravity:  "below  100°  if  sufficient  water  has  heen  added.  Natural 
rich  Jersey  milk  is  -generally  heavy.  Any  whole  milk  that 
stands  above  1.033  is  nearly  certain  to  have  been  skimmed, 
while  that  below  1.029  is  nearly  always  watered.  In  making 
corrections  for  temperature  one  hydrometer  degree  approxi- 
mately may  be  subtracted  for  each  10°  F.  below  the  standard 
of  the  hydrometer,  or  one  degree  added  for  each  10°  F.  above 
this  standard. 

The  percentage  of  cream  by  volume  is  ascertained  by  means 
of  the  creamometer,  which  is  simply  a  small  cylinder  graded  in 
hundredths  and  kept  closed  with  a  glass  stopper.  The  per- 
centage of  cream  is  quite  variable  as  to  the  amount  of  fat,  de- 
pending on  dilution,  agitation,  temperature,  and  other  factors. 
Specimens  that  contain  the  least  fat  may  yield  the  most  cream, 
and  a  milk  that  has  been  watered  will  in  a  few  hours  separate 
a  thicker  layer  of  cream  than  if  it  had  not  been  watered.  The 
amount  of  cream  that  separates  in  twenty-four  hours  is  from 
10  to  12  per  cent,  in  ordinary,  and  15  to  20  per  cent,  in  good 
milk.  Less  than  10  per  cent,  of  cream  with  a  sp.  gr.  above 
1.033  denotes  skimming.  Less  than  20  per  cent,  with  a  sp.  gr. 
below  1.029  shows  that  the  milk  has  been  watered. 

Determination  of  Total  Solids. — Weigh  into  a  tared  platinum  dish 
or  watch-glass  5  c.c.  of  milk,  evaporate  on  the  water-bath  to  dryness 
(about  three  hours),  then  transfer  to  the  water-  or  air-  oven  at  100°  C. 
until  it  ceases  to  lose  in  weight  (about  three  hours),  cool  in  desiccator, 
and  weigh. 

Determination  of  Ash. — The  mineral  residue  is  estimated  by  careful 
ignition  of  the  total  residue  at  a  dull-red  heat  until  the  organic  matter 
is  burned  off  and  the  sediment  becomes  gray-white  in  color  and  ceases 
to  lose  in  weight.  Adulteration  with  chalk,  borax,  etc.,  increases  both 
the  total  solids  and  the  ash  (above  1  per  cent.).  Phosphates,  chlorids, 
and  sulphates  may  be  separated  by  the  ordinary  tests. 

Determination  of  Fat. — In  the  Werner-Schmid  method  10  c.c.  of 
milk  are  mixed  with  10  c.c.  of  strong  HC1  in  a  long  test-tube  with  a 
capacity  of  50  c.c.  The  mixture  is  brought  to  a  boil  (till  the  liquid 
turns  deep  brown,  but  not  black) ;  then  cooled,  30  c.c.  of  ether  added, 
and  the  tube  corked  and  shaken  well.  As  soon  as  the  ether  separates, 
a  wash-bottle  cork-stopper  (lower  end  of  exit  tube  with  a  short  curve 


MILK. 


423 


and  opening  just  above  the  line  of  separation)  is  inserted  and  the  ether 
blown  oil'  into  a  tared  flask.  Ten  c.c.  more  of  ether  are  added  twice,  and 
blown  off  as  before.  The  ether  is  now  distilled  from  the  flask  and  the 
fat-residue  dried  in  the  water-oven  and  weighed. 

Another  simple  method  of  estimating  the  milk-fat  is  by  treating 
the  total  solids  with  excess  of  benzin  four  times,  boiling  down  on  the 
water-bath  each  time  to  half,  and  decanting.  The  loss  of  weight  in  the 
residue  equals  the  fat. 

Since  the  opacity  of  milk  varies  with  the  amount  of  contained  fat, 
pioscopic  methods  are  of  service  in  estimating  this  constituent.  Feser's 
lactoscope  consists  of  a  glass  cylinder  constricted  at  the  lower  closed 
end,  in  the  axis  of  which  projects  a  small  plug  of  white  glass  marked 
with  a  few  horizontal  black  lines.  Four  c.c.  of  milk  are  introduced  into 
the  instrument,  concealing  the  black  lines.  Pure  water  is  then  added, 
with  frequent  shaking,  until  the  lines  become  visible.  The  surface-level 


Fig.  51.— Feser's  Lactoscope. 


of  the  liquid  indicates  the  percentage  of  fat  in  the  specimen,  as  shown 
by  the  graduation  on  the  vessel.  With  a  little  experience  the  readings 
can  be  made  accurate  within  0.25  per  cent.  Opacity  due  to  suspended 
chalk  or  starch  is  differentiated  with  the  microscope. 

The  official  method  for  detection  of  fat  in  milk  is  that  of  Adams. 
Ten  c.c.  of  milk  is  absorbed  by  a  coiled  strip  of  fat-free  bibulous  paper, 
about  2  by  24  inches  in  size  and  tied  with  a  thread  or  wire.  This  is  dried 
on  a  watch-glass  in  the  water-oven  for  an  hour  or  more,  and  then  placed 
in  the  middle  chamber  of  a  Soxhlet  extractor.  The  tared  flask  (150  c.c.) 
at  the  bottom,  containing  75  c.c.  of  ether,  is  heated  cautiously  on  the 
water-bath.  The  ether-vapor,  condensing  in  the  upper  part  of  the  ap- 
paratus, flows  back  through  the  paper  into  the  flask.  After  ten  such 
siphon-washings,  lasting  one  to  one  and  one-half  hours,  the  flask  is  de- 
tached and  connected  with  a  condenser  and  the  ether  distilled  off.  The 
fat-residue  is  dried  in  the  air-oven  at  from  100°  to  105°,  cooled,  and 
weighed. 


424:  CLINIC  CHEMISTRY. 

The  centrifugal  method  of  separating  fat  is  very  convenient,  and 
gives  results  accurate  to  1/5  of  1  per  cent.  To  5  c.c.  of  milk  is  added, 
with  shaking,  1  c.c.  of  a  mixture  of  13  volumes  of  wood  alcohol,  37  vol- 
umes of  amyl  alcohol,  and  50  volumes  of  HCL,  and  then  the  tube  or 
bottle  is  filled  up  with  about  5  c.c.  of  strong  H2S04,  well  shaken,  and 
revolved  for  three  minutes,  when  the  percentage  of  fat  can  be  read  off 
directly. 

Estimation  of  Sugar. — This  constituent  is  fairly  constant  in  un- 
watered  milk.  Dilute  10  c.c.  of  milk  to  200  c.c.,  add  acetic  acid  gradually 
till  coagulation  takes  place,  pass  CO2  into  the  liquid  for  fifteen  minutes, 
let  stand,  and  settle.  Filter,  wash  residue,  and  coagulate  lactalbumin 
and  globulin  in  filtrate  by  boiling.  Filter  again  and  estimate  lactose  in 
filtrate  by  means  of  Purdy's  method  (see  "Urine")  or  by  Fehling's  solu- 
tion, 10  c.c.  of  which  is  decomposed  by  0.0676  gm.  lactose. 

Another  method  for  estimating  sugar  of  milk  is  to  acidulate  with 
HC1,  boil,  filter,  wash,  and  then  boil  filtrate  again  for  an  hour  or  so  to 
hydrolyze  all  the  lactose  to  glucose,  which  may  then  be  estimated  with 
Purdy's  solution. 

Estimation  of  Proteids. — Casein  can  be  pptd.  by  diluting  10  c.c. 
of  milk  with  50  c.c.  of  water,  warming  on  the  water-bath  to  40°,  adding 
2.5  c.c.  of  10-per-cent.  alum  solution,  and  stirring  thoroughly.  After 
fifteen  minutes  the  finely  flocculent  ppt.  should  be  removed  by  filtration, 
washed,  and  determined  by  the  Kjeldahl  method  for  N  (see  "Urine"), 
the  result  being  multiplied  by  6.37  to  obtain  the  weight  of  casein.  To 
the  filtrate  from  the  alum  ppt.  add  10  c.c.  of  Almens's  tannin  solution 
(10  gm.  of  tannin,  10  c.c.  of  25-per-cent.  acetic  acid,  90  c.c.  of  alcohol, 
and  100  c.c.  of  water).  This  ppts.  albumin  and  globulin,  which  may  be 
estimated  in  just  the  same  way  as  casein.  The  total  N  can  also  be 
estimated  by  placing  10  c.c.  of  milk  in  a  Kjeldahl  flask,  adding  15  c.c.  of 
H2S04,  and  testing  as  above. 

These  proteins  are  usually  determined  by  difference.  They  may 
also  be  pptd.  with  tannin.  The  ppt.  is  dried  and  washed  with  1  part  of 
alcohol  and  3  parts  of  ether  till  the  washings  show  no  trace  of  tannin 
with  iron  solution,  then  dried  and  weighed. 

In  the  Woodward  centrifugal  method  for  proteins-  5  c.c.  of  milk 
is  placed  in  each  of  two  milk-burets  and  kept  at  95°  to  100°  F.  for  18 
to  24  hours,  then  cooled  in  water.  The  milk-serum  is  now  drawn  off, 
mixed  with  10  c.c.  of  Esbach's  solution  (see  "Urine"),  and  centrifugated 
until  the  reading  is  constant.  The  volumetric  percentage  equals  the  per- 
centage by  weight  of  total  proteins. 

Short  Methods. — A  number  of  formulas  have  been  devised  by  ex- 
periment to  save  time  and  trouble  in  milk  analysis.  When  any  two  of 
the  three  data,  sp.  gr.  (G),  fat  «(F),  and  total  solids  (T)  are  known,  the 
third  can  be  calculated  by  the  following  formulas: — 

T F  +  0.2186  G  (last  two  figures) 

0.859 

F  =  0.859  T  —  0.2186  G  (last  two  figures) 

For  poor  skim-milk,  when  ^  exceeds  2.5,  this  modified  formula 
should  be  employed:  — 

F  =  0.859  T  —  0.2186  G  —  0.05  (£  —  2.5) 
The  following  is  a  formula  to  determine  the  amount  of  skimming:  — 


URINE.  425 

S  (solids  not  fat)  —  F  X  */9  =  x,  or  amount  of  fat  removed. 
The  degree  of  watering  is  estimated  by  this  formula: — 

Solids  not  fat  X  100 

— <j —  =  percentage  of  pure  milk  present. 

For  ordinary  purposes  the  residue  left  from  removal  of  the  fat  (by 
treating  with  15  volumes  of  ether  and  filtering)  is  exhausted  with  weak 
boiling  alcohol  to  extract  the  sugar.  This  is  filtered  and  the  filtrate 
evaporated  to  dryness  and  weighed.  The  second  residue  is  ignited  and 
the  proteins  determined  by  deducting  the  weight  of  the  ash. 

Microscopically  one  finds  many  leucocytes  in  cases  of 
mastitis  with  abscess-formation.  The  staphylococcus  pyogenes 
a] bus  is  nearly  always  present  in  breast-milk.  Streptococci  are 
found  in  cases  of  infection.  •  According  to  von  Jaksch,  the  tu- 
bercle bacillus  is  occasionally  present  in  the  milk  of  phthisic 
women. 

THE    URINE. 

In  the  practical  examination  of  the  urine  for  clinic  pur- 
poses one  should  have  a  part  or  the  whole  of  the  mixed  urine 
for  twenty-four  hours:  say,  from  7  A.M.  to  7  A.M.  The  urine 
is  kept  in  a  cool  place  in  a  clean,  well-corked,  half-gallon  bottle, 
into  which  has  been  dropped  2  or  3  m.  of  formalin  or  an  ounce 
of  a  saturated  aqueous  solution  of  boric  acid.  Immediately 
after  each  micturition  the  urine  passed  should  be  added  to  the 
bottle  and  the  cork  replaced. 

For  qualitative  and  microscopic  tests  for  morbid  ingre- 
dients, if  it  is  impracticable  to  save  the  day's  urine,  a  specimen 
had  best  be  taken  at  midday  or  three  or  four  hours  after  a  meal. 
The  early  morning  urine  is  least  likely  to  contain  albumin  or 
other  abnormal  ingredients. 

For  the  quantitative  estimation  of  both  normal  and  abnor- 
mal ingredients,  centrifugal  methods  are  especially  rapid  and 
convenient  and,  if  properly  performed,  sufficiently  accurate. 
The  percentage  of  sediment  will  vary  obviously  with  the  rate 
and  period  of  revolution,  as  well  as  the  diameter  of  the  cen- 
trifuge. Purdy  recommends  1200  revolutions  per  minute  with 
a  centrifuge  having  a  radius  (including  the  tube)  of  6  3/4  inches, 
and  best  operated  by  means  of  water-power  or  the  electric  mo- 
tor, so  as  to  insure  a  steady  rate.  In  most  instances  he  directs 
to  mix  the  urine  with  the  reagent  by  inverting  the  tube  3  times, 
then  let  stand  3  minutes  to  insure  thorough  reaction,  and  then 
revolve  3  minutes  at  the  uniform  rate  mentioned. 


426 


CLINIC  CHEMISTRY. 


GENERAL  PROPERTIES. 

COLOR. 

The  color  of  the  urine  is  due  chiefly  to  urochrom  and  uro- 
bilin  (urohematin),  both  of  which  are  derivatives  of  bilirubin. 
The  average  color  is  amber,  but  it  varies  normally  from  almost 
colorless  to  reddish  brown,  depending  on  the  degree  of  concen- 
tration as  determined  by  eating,  drinking,  exercise,  the  use 
of  diuretics,  and  the  activity  of  the  skin,  lungs,  and  bowels. 


Fig.  52.— Purdy's  Electric  Centrifuge. 


Vogel  has  arranged  a  color-scale  of  nine  colors  in  three  groups, 
namely:  yellow,  red,  and  brown  or  black.  To  make  compari- 
sons with  this  scale  the  clear  or  filtered  urine  should  be  exam- 
ined by  transmitted  light  in  a  glass  vessel  three  or  four  inches 
in  diameter. 

The  urine  darkens  slightly  on  standing  until  it  becomes 
alkaline,  when  it  becomes  lighter.  It  is  darkened  by  meat  or 
strong  coffee;  turned  reddish  by  beets  and  bilberries  (violet, 
if  alkaline);  brown  or  yellow  by  carrots  and  rhubarb;  much 
milk  in  the  diet  gives  a  greenish  tinge. 


PLATE  V. 


Pale  Yellow*. 


Light  Yellow. 

3 

Yellow. 


ReddishYellow. 


Yellowish  Red. 

6. 
Red. 


Brownish  Red. 


Reddish  Brown. 


9. 

Brownish  Black. 


fh>mNature  lyDrJ".  Voyel 

VOGEL'S  SCALE  OF  URINE  TINTS. 


URINE.  427 

Many  drugs  affect  the  color  of  the  urine.  It  is  colored 
green  by  saffron  or  salicylic  acid;  orange  by  chrysophanic  acid 
or  santonin  (carmin,  if  alkaline);  brown  by  chelidonium  or 
senna  (blood-red,,  if  alkaline);  smoky  brown  or  black  from  tar, 
salol,  gallic  acid,  resorcin,  uva  ursi,  or  naphtalin;  reddish  from 
logwood  (alkaline,  violet)  or  fuchsin;  bright  yellow  from  picric 
acid;  blue  from  methylene  blue  (often  greenish)  or  methyl 
violet. 

Pathologically  the  urine  is  very  pale  in  hysteria,  dread, 
and  anxiety;  after  convulsions,  and  in  diabetes  insipidus.  In 
diabetes  mellitus  it  is  pale  and  opalescent,  often  with  a  green- 
ish tinge  if  there  is  much  sugar.  It  is  also  pale  in  chronic  in- 
terstitial nephritis,  amyloid  disease,  hydronephrosis,  anemia, 
chlorosis,  and  convalescence  from  acute  affections.  Milky  urine 
is  noted  in  pyuria  (pyelitis,  cystitis,  gonorrhea),  phosphaturia, 
and  chyluria. 

The  urine  is  generally  high-colored  in  renal  congestions, 
acute  nephritis,  and  acute  febrile  and  inflammatory  diseases. 
It  is  rendered  darker  by  concentration  from  any  cause  (diar- 
rhea, vomiting,  sweating  freely)  and  in  melancholia.  In  hema- 
turia  (cancer,  sarcoma,  or  trauma)  the  blood  is  red  or  smoky; 
in  hematinuria  it  is  smoky  brown  or  even  black;  in  hemoglobi- 
nuria  (malaria,  scarlet  fever,  KC103  poisoning)  it  is  pink  or 
even  porter-colored.  Carbolic  acid  poisoning  renders  the  urine 
dark  brown  to  greenish  black,  especially  on  standing,  from  oxi- 
dation of  pyrocatechin;  the  same  color  is  noted  in  poisoning 
by  creasote,  cresol,  guaiacol,  cyanids,  or  arsin.  In  sulphonal 
poisoning  the  urine  is  colored  brown  red,  from  hematopor- 
phyrin. 

Choluria,  or  the  presence  of  bile,  is  marked  by  a  bright- 
yellow  to  green-brown  or  porter  color,  with  a  yellow  foam  on 
shaking.  It  is  dark  yellow,  nearly  black,  in  pathologic  uro- 
bilinuria  and  indicanuria.  The  normal  yellow  hue  gradually 
turns  black  in  melanuria  and  alkaptonuria;  the  change  takes 
place  at  once  on  adding  oxidizing  agents,  such  as  HN~03  or 
Fe2Cl6.  A  mixture  of  urates  and  phosphates  or  pus  and  phos- 
phates exhibits  a  dark-gray  appearance. 

The  urine  is  purple  or  pinkish  in  color,  from  excess  of 
urates,  in  acute  gout,  rheumatism,  and  liver  disorders  (lithe- 
mia).  It  is  rosy  in  chyluria  with  hematuria,  due  to  filariasis. 
It  rarely  shows  a  dirty-blue  or  green  scum  in  cholera,  typhus, 
cystitis,  or  nephritis,  from  decomposition  of  excess  of  indican. 
In  trional  poisoning  it  shows  a  cherry  tinge.  In  bacteriuria  the 
urine  is  grayish  and  opalescent. 


428  CLINIC  CHEMISTRY. 

ODOR. 

The  slightly  aromatic  odor  of  fresh  urine  is  due  to  minute 
amounts  of  phenylic,  taurylic,  damolic,  and  damoluric  acids  and 
volatile  ethers.  The  strong  urinous  odor  of  decomposed  sam- 
ples is  due  to  ammonium  carbonate  and  sulphid. 

The  more  concentrated  the  urine,  the  stronger  is  its  odor. 
On  standing  for  some  days  (sooner  in  warm  weather)  it  becomes 
ammoniacal  and  putrescent.  Characteristic  odors  are  imparted 
by  the  ingestion  of  asparagus,  asafetida,  cabbage,  carbolic  acid, 
cauliflower,  copaiba,  cubebs,  garlic,  parsnips,  saffron,  santal-oil, 
spices,  Tolu,  valerian,  etc.  Turpentine  and  terebene  give  a 
scent  like  violets. 

Urine  which  is  pungent  and  ammoniacal  when  first  passed 
is  characteristic  of  chronic  cystitis  or  paralytic  retention.  It 
is  peculiarly  putrid  in  pyelitis.  The  aroma  is  sweet  and  fruity 
or  hay-like  in  diabetes  mellitus,  becoming  alcoholic;  in  ace- 
tonuria  it  is  like  apples  or  chloroform.  The  smell  is  offensive, 
like  stale  fish,  in  bacteriuria.  It  is  almost  absent  in  obstructive 
retention,  forming  cysts.  A  fecal  odor  is  a  sign  of  a  recto- 
vesic  fistula  or-abscess.  The  urine  is  fragrant,  like  sweet-brier, 
in  cystinuria;  but  when  the  cystin  decomposes  it  smells  like 
sewer-gas. 

TRANSPARENCY. 

Normal  urine  is  quite  clear  when  freshly  passed.  On  stand- 
ing a  slight  cloud  of  mucus  and  epithelia  forms  near  the  bottom 
in  a  few  minutes;  on  cooling  to  near  f.p.  a  "brick-dust"  sedi- 
ment of  acid  urates  is  frequently  seen,  especially  if  the  urine 
is  scanty;  it  becomes  dull  and  opaque  from  fission-fungi  in 
twenty-four  to  forty-eight  hours;  alkaline  fermentation  is  ac- 
companied by  cloudiness,  due  to  earthy  and  triple  phosphates, 
ammonium  urate,  and  bacteria.  Diminished  pigmentation  tends 
to  ppt.  uric  acid  crystals.  A  temporary  cloudiness  occurs  from 
excess  of  vegetable  food-salts  or  from  mental  strain  (fixed  alka- 
line reaction).  Permanent  cloudiness,  or  "phosphaturia,"  de- 
pends on  low  acidity,  with  consequent  precipitation  of  earthy 
phosphates,  and  is  due  to  nervous  debility  or  indigestion  with 
hyperchlorhydria.  The  urine  is  often  turbid  in  fevers  from 
precipitation  of  urates  (white,  yellow,  brown,  or  pink).  Crystal- 
line sodium  urate  is  occasionally  observed  in  acute  febrile 
diseases  of  children.  A  deposit  of  uric  acid  and  urates  within 
three  or  four  hours  takes  place  in  disorders  of  the  digestive 
apparatus;  this  precipitation  takes  place  at  once  or  nearly  so 
in  calculus.  Early  deposition  of  the  acid  also  occurs  in  con- 
valescence from  febrile  complaints,  particularly  articular  rheu- 


URINE.  429 

matism;  the  middle  period  of  chronic  interstitial  nephritis; 
chorea,  diabetes,  and  enlarged  spleen.  Infarcts  of  uric  acid  are 
common  in  infants,  who  strain  and  cry  out  when  passing  water; 
there  is  then  found  a  pink  or  yellowish  sandy  deposit  on  the 
diapers. 

The  presence  of  a  sediment  of  a  normal  ingredient  is  no 
indication  whatever  of  excess  or  of  the  amount  in  any  way;  but 
rather  of  some  change  in  the  reaction  or  concentration  of  the 
urine.  The  following  short  list  will  aid  in  differentiating  the 
most  common  forms  of  sediment  and  cloudiness: — 

1.  Turbidity  cleared  by  heat  (below  b.p.)  or  an  alkaline 
hydrate  =  urates  (acid  varieties,  pink,  yellow,  or  fawn-colored; 
ammonium  urate,  white). 

2.  Not  cleared  by  heat,  but  with  acetic  acid  =  phosphates 
(whitish). 

3.  Insoluble  in  acetic,  but  soluble  in  hydrochloric,  acid  = 
calcium  oxalate  (whitish,  resembling  cloud  of  mucus,  and  mixed 
with  it;   "envelope"  microscopic  crystals). 

4.  Cleared  up  by  ammonium  hydrate,  but  not  by  heat  = 
cystin  (greenish). 

5.  Intensified  more  or  less  by  heat  and  acids: — 

Blood:  red,  smoky,  or  chocolate  brown;  microscopic  cor- 
puscles. 

Mucus:   white  and  stringy;   liquefied  by  liquor  potassse. 

Pus:  white  and  creamy;  made  gelatinous  by  liquor  po- 
tassae. 

Semen  or  epithelia:  both  diagnosed  only  with  the  micro- 
scope. 

6.  Unaffected  by  heat,  chemic  agents,  or  filtration  —  bac- 
teria (colon  bacilli,  bacterium,  and  micrococcus  ureas;   mold  or 
yeast-plants,  and  specific  germs). 

7.  Granular  precipitate  resembling  Cayenne  pepper  (some- 
times brown  or  yellow  and  rarely  white)  =  uric  acid. 

8.  Milky  appearance,  most  marked  near  top  of  fluid  =  fat 
or  chyle  (both  cleared  up  by  shaking  with  ether). 

CONSISTENCE. 

Normal  urine  is  limpid  and  nearly  aqueous.  It  is  thick, 
viscid,  and  ammoniacal  in  chronic  cystitis.  In  fibrinuria  it 
gelatinizes  on  standing,  forming  a  grayish  coagulum  insoluble 
in  water,  but  dissolved  by  pepsin  and  1-per-cent.  HC1.  In 
chyluria  with  fibrinuria  the  pink  urine  may  coagulate  before 
voiding.  The  presence  of  albumin,  sugar,  or  bile  gives  rise  to 
a  persistent  foam  on  shaking. 


430  CLINIC  CHEMISTRY. 

CHEMIC   REACTION. 

The  reaction  of  the  urine  is  normally  slightly  acid  (alkaline 
as  it  leaves  the  capsule)  and  due  to  NaH2P04,  which  is  derived 
from  the  Na2HP04  of  the  blood  by  reaction  with  carbonic,  uric, 
hippuric,  and  sulphuric  acids.  The  degree  of  acidity  is  esti- 
mated in  the  usual  way  with  decinormal  alkali,  using  litmus  as 
an  indicator.  The  mixture  of  acid  and  neutral  phosphates  in- 
terferes with  the  end-reaction,  making  the  findings  a  trifle  high. 
The  total  acidity  corresponds  to  2  to  4  gm.  of  oxalic  acid. 

The  urine  is  sometimes  alkaline  after  meals,  especially  if 
much  vegetable  food  has  been  taken,  said  alkalinity  being  due 
to  the  carbonates  and  bicarbonates  of  the  alkali  metals.  It  is 
occasionally  amphoteric,  from  the  presence  of  both  acid  and 
neutral  phosphates. 

On  standing  acid  urine  often  becomes  more  acid,  from 
enzyme  action  of  mucus  on  coloring  matters,  causing  lactic  and 
acetic  acid  fermentation;  in  four  or  five  days  (sooner  if  warm 
weather,  or  if  feebly  acid  and  of  low  density)  it  always  under- 
goes ammoniacal  fermentation  from  the  action  of  the  fission- 
fungi  on  urea:— 

N2H4CO  +  2H20  =  2(NH4)2C03 

Urinary  acidity  is  increased  by  excess  of  meat,  .prolonged 
muscular  exercise,  and  ingestion  of  saccharin  and  mineral  or 
benzoic  acids.  Alkalinity  (fixed)  is  favored  by  a  vegetable  diet, 
hot  or  cold  baths,  free  perspiration,  and  alkaline  hydrates  or 
carbonates  and  salts  of  vegetable  acids.  The  normal  acidity  is 
decreased  after  meals,  often  becoming  neutral  in  three  to  five 
hours,  rising  again  as  the  food  passes  into  the  intestines. 

Pathologically  the  urine  is  sharply  acid  in  lithemia,  gout, 
acute  rheumatism,  diabetes,  pleurisy,  pneumonia,  and  other  in- 
flammations; also  in  starvation,  scurvy,  leukemia,  and  chronic 
interstitial  nephritis.  Its  hyperacidity  in  gastric  achlorhydria 
is  due  to  free  fatty  acids  (lipaciduria). 

Fixed  alkalinity  is  distinguished  by  the  fact  that  the  red 
color  of  the  litmus-paper  is  not  restoied  by  drying.  It  is  noted, 
with  deposit  of  earthy  phosphates  ("phosphaturia"),  in  chlorosis, 
anemia,  general  debility,  nervous  dyspepsia,  organic  nervous 
diseases,  resorption  of  alkaline  transudates,  atrophic  gastritis, 
and  when  there  is  loss  of  gastric  juice  by  fistula  or  vomiting. 
Much  blood  or  pus  in  the  urine  also  causes  fixed  alkalinity. 

The  volatile  alkalinity  of  ammoniacal  urine  is  shown  by 
the  red  color  of  litmus  being  restored  on  drying.  It  is  observed 
in  freshly  passed  urine,  with  deposit  of  earthy  and  triple  phos- 


URINE.  431 

phates,  in  chronic  cystitis  and  in  retention  of  urine  due  to  para- 
plegia, myelitis,  enlarged  prostate,  or  urethral  stricture. 

The  normal  digestive  curve  is  always  increased  in  gastro- 
succorrhea;  it  is  absent  in  atrophic  gastritis,  severe  chronic  gas- 
tritis, and  cancer  of  the  stomach. 

DAILY   QUANTITY. 

This  ordinarily  ranges  from  1000  to  1200  c.c.  for  men;  900 
to  1000  c.c.  for  women;  and  for  children  relatively  more  than 
for  adults  in  proportion  to  body-weight.  More  is  passed  in  the 
afternoon,  less  in  the  forenoon,  and  least  at  night;  the  maxi- 
mum is  a  few  hours  after  meals.  High  altitudes  and  the  sum- 
mer season  decrease  the  quantity  of  urine. 

The  quantity  of  urine  is  increased  by  cold  and  a  moist 
atmosphere,  nervous  excitement,  moderate  exercise,  liberal  po- 
tations, and  the  use  of  diuretics,  including  alcohol  and  sugar. 
The  quantity  is  decreased  by  vicarious  action  of  the  skin,  bow- 
els, or  lungs;  by  rest;  and  by  fluid  or  dietary  abstinence. 

Permanent  polyuria  is  observed  in  both  forms  of  diabetes 
and  in  chronic  interstitial  nephritis;  also  in  amyloid  kidney, 
cystic  renal  degeneration,  renal  tuberculosis,  pyelitis,  constipa- 
tion, cardiac  hypertrophy,  and  in  organic  nervous  lesions,  espe- 
cially of  medulla  (sugar  also  present  in  about  half  the  cases  of 
hemorrhage). 

Temporary  or  paroxysmal  polyuria  is  noted  in  hydro- 
nephrosis,  alternating  with  periods  of  diminution;  in  conva- 
lescence from  acute  affections,  particularly  with  resorption  of 
serous  effusions;  also  in  hysteria  (hydruria),  excitement,  and 
some  cases  of  nervous  debility,  convulsions,  chorea,  and  mi- 
graine. 

Oliguria  is  seen  especially  in  acute  and  chronic  diffuse 
nephritis  and  in  renal  congestion  (increased  quantity  in  first 
stage  of  active  variety)  from  cantharides,  turpentine,  etc. 
Other  causes  of  diminished  urine  are  the  fastigium  and  defer- 
vescence of  acute  fevers,  diarrhea,  dysentery,  cholera,  persistent 
vomiting,  gastric  dilation,  pyloric  stenosis,  cardiac  dilation 
and  insufficiency,  chronic  lead  poisoning,  hepatic  cirrhosis  with 
dropsy,  melancholia,  emphysema,  and  chronic  bronchitis.  In 
renal  calculus  the  amount  of  urine  is  temporarily  diminished, 
with  pain  and  frequent  micturition,  becoming  copious  when  the 
obstruction  is  removed. 

Partial  or  complete  suppression  (anuria)  is  sometimes 
noted  in  acute  and  chronic  nephritis,  and  following  ether  anes- 
thesia, reflex  shock  from  operation  (particularly  genito-urinary), 
catheterization  (urinary  fever),  internal  injuries,  severe  hemor- 


432  CLINIC  CHEMISTRY. 

rhages,  or  strangulated  bowel.  Obstructive  suppression  is  en- 
countered when  the  ureter  is  plugged  by  a  calculus  and  the 
other  kidney  is  absent  or  non-functionating;  obstruction  of 
ureters  by  a  colon  growth  or  by  a  tumor  at  the  vesic  orifices; 
and  by  irritation  reflected  to  the  kidneys  from  a  diseased  blad- 
der, enlarged  prostate,  or  old  stricture  (this  form  is  transient 
and  may  follow  a  debauch).  Suppression  is  also  noted  in  some 
cases  of  hysteria,  puerperal  eclampsia,  the  algid  stage  of  cholera, 
grave  fevers  and  inflammations,  and  toward  the  fatal  end  of 
renal  and  other  diseases.  In  thrombosis  of  the  renal  vein 
anuria  is  preceded  by  the  passage  of  blood  and  blood-casts.  In 
obstructive  suppression  the  urine  is  pale  and  watery,  with  no 
albumin  or  casts,  as  a  rule.  In  non-obstructive  suppression  the 
urine  is  concentrated  and  is  likely  to  contain  albumin,  blood, 
and  casts.  Eetention  of  urine  in  the  bladder  may  be  due  to 
urethral  obstruction  or  a  paralyzed  bladder,  and  is  readily  diag- 
nosed by  percussion  and  catheterization.  Saline  diuretics  act 
by  increasing  osmotic  pressure  of  plasma,  causing  hydremic 
plethora  and  consequent  rise  of  blood-pressure. 


SPECIFIC   GRAVITY. 

This  is  determined  by  means  of  a  urinometer  and  jar,  or 
more  exactly  by  the  Westphal  balance.  The  best  urinometer  is 
that  of  Squibb,  with  a  spindle-shaped  bulb  and  a  fluted  cylinder. 
When  the  temperature  of  the  urine  is  not  the  same  as  the 
standard  of  the  instrument,  about  7°  may  be  allowed  for  each 
degree  above  or  below  this  standard. 

The  normal  sp.  gr.  of  urine  ranges  from  1.015  to  1.025. 
In  young  infants  it  is  often  below  1.005.  The  sp.  gr.  varies 
inversely  with  the  quantity,  as  a  rule;  hence,  is  higher  in  sum- 
mer than  in  winter.  It  is  raised  by  excess  of  proteid  foods  or 
salts,  active  muscular  exercise,  and  copious  diaphoresis.  It  is 
lowered  by  fasting,  chilling,  nervous  excitement,  milk  and  vege- 
table diet,  and  the  imbibition  of  much  fluid. 

Pathologically  the  urine  is  of  high  sp.  gr.  in  acute  fevers 
and  inflammations,  melancholia,  most  cases  of  functional  albu- 
minuria,  acute  diffuse  nephritis,  cyanotic  renal  induration,  and 
markedly  with  polyuria  in  diabetes  mellitus. 

A  low  sp.  gr.  is  the  rule  in  all  forms  of  Bright's  disease 
(with  oliguria  or  polyuria)  and  renal  insufficiency  except  the 
two  above  mentioned.  A  fall  of  density  may  precede  uremic 
convulsions  for  several  days.  The  density  is  also  reduced  in 
diabetes  insipidus  (may  be  1.000  to  1.005),  hysteria,  anemia, 
chlorosis,  and  most  chronic  diseases  attended  with  inanition; 


URINE.  433 

serous  exudations  (dropsy  or  edema);  after  copious  sweating, 
vomiting,  or  diarrhea;  in  convalescence  from  acute  diseases, 
and  toward  the  fatal  end  of  acute  maladies.  A  low  sp.  gr.  with 
a  high  color  is  specially  significant  of  the  approach  of  death 
in  chronic  diseases.  Generally  speaking,  decrease  of  sp.  gr. 
without  a  corresponding  increase  of  water  is  a  bad  sign. 


TOTAL   SOLIDS. 

The  average  daily  quantity  of  total  solids  in  the  male  adult 
is  about  70  gm.,  of  which  nearly  V2  is  urea,  V5  NaCl,  and  1/25 
phosphates.  In  each  1000  c.c.  of  urine  there  are  about  967 


Fig.  53. — Squibb's  Urinometer. 


parts  of  water  and  33  parts  of  solids,  2/3  being  organic  and  V3 
inorganic. 

The  total  solids  in  gm.  per  1000  c.c.  can  be  calculated  ap- 
proximately by  multiplying  the  last  two  figures  of  the  sp.  gr. 
by  2  Y3;  this  is  called  Haeser's  coefficient.  Another  method 
to  find  the  amount  of  solids  in  grains  is  to  multiply  the  last 
two  figures  of  the  sp.  gr.  by  the  number  of  ounces  of  urine  daily, 
then  add  to  the  product  yM  of  itself.  Ten  per  cent,  should  be 
deducted  from  the  total  solids  for  persons  between  40  and  50; 
20  per  cent,  between  50  and  60;  30  per  cent,  between  60  and 
70;  and  50  per  cent,  above  70.  Deduct  1/3  from  total  average 
of  solids  in  persons  who  have  fasted  for  two  or  more  days;  for 
total  rest  deduct  Y10. 


434  CLINIC  CHEMISTRY. 


NORMAL  CONSTITUENTS. 

CHLORIDS. 

These  are  derived  entirely  from  the  chlorids  of  the  food, 
chiefly  NaCI,  and  amount  to  10  to  16  gm.  daily.  The  amount 
excreted  also  varies  directly  with  the  volume  of  urine.  It  is 
decreased  by  rest,  increased  by  exercise.  The  digestive  curve 
of  chlorids  corresponds  closely  with  the  curve  of  acidity. 

Pathologically  an  absolute  increase  is  noted  in  diabetes 
insipidus,  Bright's  disease,  after  epileptic  attacks,  in  the  de- 
clining stage  of  dropsy  (resorption),  and  after  the  crisis  of  acute 
fevers  and  inflammations  (resorption);  also  in  prurigo  and  in- 
termittent fever. 

An  absolute  decrease  is  observed  before  and  up  to  the 
febrile  crisis,  particularly  in  pneumonia,  in  which  chlorids  may 
be  even  temporarily  absent.  A  decrease  is  also  found  in  pleu- 
risy, the  nephritides,  anemia,  cachectic  conditions,  and  chronic 
dropsic  complaints;  chronic  lead  poisoning;  chronic  mental 
diseases;  cholera,  diarrhea,  and  vomiting;  acute  articular  rheu- 
matism; gastrectasis  with  pyloric  stenosis;  hyperchlorhydria, 
or  gastric  carcinoma.  In  benign  pyloric  stenosis  there  is  a 
small  amount  of  chlorids  and  also  of  N";  little  chlorids  with 
relatively  large  amount  of  N"  in  malignant  stenosis. 

Estimation  of  Chlorids.  Mohr's  Volumetric  Method. — Take  10  c.c. 
of  urine,  dilute  with  50  c.c.  or  more  of  ELO,  add  1/2  c.c.  of  20-per-cent. 
K2Cr04  (indicator),  then  titrate  with  standard  AgNO3  solution  (same  as 
for  sanitary  analysis  of  water)  until  a  permanent  pink  or  orange  color 
appears.  Each  c.c.  of  the  standard  solution  used  is  equivalent  to  0.01 
gm.  NaCl  or  0.006065  gm.  01.  One  c.c.  of  the  standard  solution  should 
be  subtracted,  so  as  to  allow  for  small  quantities  of  organic  substances 
that  react  with  the  silver  salt. 

Purdy's  Centrifugal  Method. — To  10  c.c.  of  urine  add  1  c.c.  of 
strong  HN03  and  4  c.c.  of  AgNO3  (dram  to  ounce).  Invert  3  times,  let 
stand  for  3  minutes,  then  revolve  for  3  minutes  at  1200  revolutions. 
The  percentage  by  weight  of  Cl  equals  1/12  of  the  bulk  percentage  (usually 
10  to  12  per  cent.). 

PHOSPHATES. 

The  earthy  phosphates  (Ca  and  Mg)  amount  to  1  to  1.5 
gm.  daily  and  are  derived  chiefly  from  the  food  and  partly  from 
the  breaking  down  of  nuclein  and  lecithin.  The  alkaline  phos- 
phates, from  similar  sources,  amount  to  2  to  4  gm.  in  twenty- 
four  hours. 

The  total  phosphoric  acid  is  increased  by  a  meat  diet,  fast- 
ing, and  cerebral  excitants.  It  is  decreased  on  a  vegetable  diet, 
by  pregnancy,  and  by  cerebral  depressants. 


URINE.  435 

The  earthy  phosphates 'are  increased  in  rickets  (children) 
or  osteomalacia  (adults),  chronic  rheumatoid  arthritis,  diffuse 
periostitis;  neurasthenia,  melancholia,  general  debility,  mental 
overwork,  and  central  nervous  diseases  (epilepsy,  meningitis); 
and  in  tuberculosis,  carcinoma,  leukemia,  and  acute  yellow 
atrophy. 

The  alkaline  phosphates  are  greatly  augmented  in  "phos- 
phatic  diabetes":  an  affection  characterized  by  acid  polyuria, 
thirst,  rapid  emaciation,  great  nervous  irritability,  dyspepsia, 
and  distressing  lumbar  pains. 

Both  kinds  of  phosphates  are  diminished  in  all  forms  of 
Bright's  disease  and  renal  insufficiency  and  in  chronic  lead  poi- 
soning. Less  important  is  the  decrease  noticed  in  gout,  rheu- 
matism, intestinal  indigestion,  anemia,  chlorosis,  empyema, 
hepatic  cirrhosis,  acute  yellow  atrophy,  and  intermittent  and 
most  acute  fevers  except  meningitis. 

Earthy  phosphates  are  held  in  solution  in  the  urine  by  the 
acid  reaction  and  by  C02.  Heat  drives  off  this  gas  and  so  ppts. 
the  earthy  phosphates.  Alkaline  phosphates  are  never  sponta- 
neously pptd. 

The  ratio  of  N  to  P205  in  the  urine  (normally  100  to  17) 
is  greatly  increased,  and  may  be  doubled  in  malignant  diseases 
generally. 

Volumetric  Determination  of  Total  Phosphoric  Acid  (Ogden). — 
Three  reagents  are  used:  1.  A  standard  solution  of  pure  uranium  ni- 
trate, containing  35.5  gm.  per  liter  of  distilled  water;  each  c.c.  corre- 
sponds to  0.005  gm.  P205.  2.  A  solution  of  100  gm.  of  sodium  acetate 
and  100  c.c.  of  30-per-cent.  acetic  acid  in  sufficient  distilled  water  to 
make  a  liter.  3.  A  cochineal  tincture  prepared  by  digesting  a  few  gm. 
of  cochineal  with  250  c.c.  of  diluted  alcohol  (1  part  to  3  of  water)  and 
filtering  after  several  hours.  Take  50  c.c.  of  the  urine,  add  5  c.c.  of  No. 
2  and  a  few  drops  of  No.  3,  and  warm  mixture  to  80°  C.  over  the  water- 
bath.  Then  titrate  the  hot  mixture  with  solution  No.  1  until  a  faint, 
but  distinct,  permanent  green  color  appears  to  mark  the  reaction  with 
U  as  soon  as  the  phosphoric  acid  is  entirely  pptd. 

Purdy's  Centrifugal  Method. — To  10  c.c.  of  the  urine  add  2  c.c. 
of  50-per-cent.  acetic  acid  and  3  c.c.  of  5-per-cent.  solution  of  uranium 
nitrate.  Invert  3  times,  let  stand  3  minutes,  and  revolve  for  3  minutes 
at  1200  revolutions  per  minute.  The  percentage,  by  weight,  of  P^Os 
equals  Vss  of  the  bulk  percentage  of  uranyl  phosphate  [H(UO2)PO4], 
usually  from  8  to  10  per  cent. 

To  separate  the  earthy  from  tjie  alkaline  phosphates,  the 
first  step  in  Cook's  centrifugal  test  for  uric  acid  may  be  fol- 
lowed, and  then  the  above  reagents  added.  It  should  not  be 
forgotten  that  "phosphaturia"  depends  not  on  the  amount  of 
earthy  phosphates,  but  on  the  neutral  or  alkaline  reaction  of 
the  urine. 


436  CLINIC  CHEMISTRY. 

CAKBONATES. 

A  liter  of  normal  human  urine  contains  40  to  50  c.c.  of 
C02;  if  neutral  or  alkaline,  over  100  c.c.  This  forms  both  nor- 
mal and  acid  salts  with  the  alkalies  and  alkaline  earths.  The 
amount  of  carbonates  in  normal  urine  is  generally  minute,  ex- 
cept after  the  administration  of  the  salts  of  the  vegetable  acids 
or  the  ingestion  of  these  acids  as  foods  or  medicine,  giving  rise 
to  fixed  alkalinity.  Ammonium  carbonate  in  appreciable  quan- 
tity in  freshly  passed  urine  indicates  decomposition  of  the  fluid 
within  the  bladder,  nearly  always  from  chronic  cystitis. 

The  amount  of  iron  present  in  the  residue  from  a  liter  of 
urine  varies  from  3  to  11  mg. 

SULPHATES. 

The  mineral  sulphates  (mostly  K  and  Na)  amount  from 
1.5  to  3  gm.  daily,  and  are  derived  chiefly  from  meat  and  mus- 
cle, the  contained  S  being  oxidized  to  H2S04,  and  this  uniting 
with  the  metals. 

The  proportion  of  mineral  sulphates  is  increased  by  meat 
diet,  active  exercise,  inhalations  of  pure  0,  and  ingestion  of  S 
compounds.  It  is  decreased  by  a  vegetable  diet  or  salicylates. 

Pathologically  the  mineral  sulphates  show  an  absolute  in- 
crease in  acute  fevers  and  inflammations,  especially  rheumatism, 
pneumonia,  cerebritis,  meningitis,  and  myelitis;  also  in  ob- 
structive jaundice  and  both  kinds  of  diabetes.  A  subnormal 
quantity  is  noted  in  acute  and  chronic  renal  diseases,  eczema, 
chlorosis,  leukemia,  and  carbolic  acid  poisoning  (combines  with 
H2S04  to  form  phenol-potassium  sulphate).  Generally  an  in- 
crease or  decrease  of  mineral  sulphates  runs  parallel  with  that 
of  urea. 

Centrifugal  Estimation  (Purdy). — To  10  c.c.  of  urine  add  5  c.c. 
standard  BaCl2  solution  (4  parts  of  BaCl2,  1  part  of  strong  HC1,  and  16 
parts  of  distilled  water).  Let  stand  3  minutes  after  shaking,  and  re- 
volve 3  minutes.  The  percentage  by  weight  of  S03  equals  1/4  bulk  per- 
centage of  BaS04. 

The  conjugate  or  ethereal  sulphates  originate  chiefly  from 
intestinal  putrefaction,  being  formed  in  the  liver  from  phenol,, 
skatol,  paracresol,  and  indol.  The  principal  members  of  the 
group  are  indoxyl-potassiu^n  sulphate,  or  "indican"  (C8H6- 
NO.S02.OK),  phenol-potassium  sulphate  (C6H5OS03K),  and 
skatoxyl-potassium  sulphate  (C9H8NO.S02K).  The  ratio  of 
ethereal  to  mineral  sulphates  is  normally  about  1  to  10. 

Indican  occurs  in  excess  on  a  meat  diet;  also  in  hypo- 
and  achlor-  hydria,  constipation,  and  sometimes  in  diarrhea> 


URINE.  437 

peritonitis,  perityphlitis,  typhoid  fever,  dysentery,  empyema, 
hepatic  or  gastric  carcinoma,  putrid  bronchitis,  pulmonary 
gangrene,  pernicious  anemia,  Addison's  disease,  resorption  of 
extravasations,  and  later  stage  of  phthisis  and  all  wasting 
diseases.  An  enormous  excess  is  often  noted  in  cholera  and 
intestinal  obstruction  or  tuberculosis. 

Clinic  Test  for  Indican. — To  V,  test-tube  of  urine  add  V«  as 
much  HC1  and  a  few  crystals  of  KNO3.  Boil  the  mixture,  let  cool,  and 
shake  with  2  c.c.  of  chloroform.  If  indican  is  normal  in  amount,  the 
layer  of  CHC13  will  be  colorless.  If  indican  is  in  excess,  the  chloroform 
on  settling  will  be  colored  light  blue  to  a  deep  purple,  depending  on 
the  amount. 

Clinic  Test  for  Phenol-potassium  Sulphate. — Distil  25  c.c.  of  the 
urine  with  5  per  cent,  of  H2SO4  and  add  Br  water  to  the  distillate,  get- 
ting a  yellowish  ppt.  of  tribromphenol. 

Salkowski's  Method  for  Total  Sulphuric  Acid  (Preformed  and 
Conjugate  S03). — Take  100  c.c.  of  urine  in  a  beaker,  acidulate  with  5 
c.c.  HC1,  boil,  and  add  BaCJ2  until  no  more  ppt.  ensues.  Collect  ppt.  on 
a  small  filter  of  known  ash,  and  wash  with  hot  distilled  water  till  BaCl2 
disappears  from  filtrate.  Then  wash  with  hot  alcohol  and  again  with 
ether.  Incinerate  filter-paper  and  contents  in  a  Pt  crucible,  cool,  add  a 
few  drops  of  H2SO4  (to  change  any  BaS  to  BaSOJ,  heat  again  to  red- 
ness, cool  in  a  desiccator,  weigh,  and  deduct  weight  of  crucible  and  ash. 
100  parts  of  BaS04  =  34.33  parts  S03. 

Salkowski's  Method  for  Ethereal  Sulphates.— Take  100  c.c.  of 
clear,  filtered  urine;  mix  with  an  equal  volume  of  alkaline  BaCl2  solu- 
tion [1  part  cold,  saturated  BaCl2;  2  parts  cold,  saturated  Ba(HO)2]; 
and  stir  thoroughly.  After  a  few  minutes  filter  into  a  dry  graduate  up 
to  the  100  c.c.  mark  (half  the  urine),  acidulate  this  portion  with  10  c.c. 
HC1,  boil,  keep  at  100°  C.  for  an  hour  on  the  water-bath,  and  allow  to 
stand  for  twenty-four  hours  or  until  completely  settled.  Then  wash, 
dry,  and  weigh  as  for  total  sulphates.  The  difference  between  the  total 
and  the  combined  or  ethereal  sulphates  represents  the  preformed  or 
mineral  sulphates. 

UREA. 

This  compound  is  formed  principally  in  the  liver  from  the 
synthesis  of  C02  and  NH3,  with  elimination  of  water.  It  is  in 
part  the  product  of  retrograde  metamorphosis  of  the  tissues, 
blood,  and  secretions,  and  to  a  minor  extent  it  results  from  the 
splitting  up  of  unassimilated  nitrogenous  food,  its  antecedent, 
in  this  event,  being  leucin  principally.  About  85  per  cent,  of 
the  N  taken  into  the  body  by  way  of  nourishment  is  excreted 
as  urea,  and  approximately  VT  of  the  total  potential  energy  of 
foods  consumed  escapes  unutilized  in  the  form  of  this  com- 
pound. 

Urea  is  a  neutral,  crystalline  substance  with  a  bitter,  cool- 
ing taste  like  that  of  saltpeter.  It  is  highly  soluble  in  water, 
and  is  used  as  a  diuretic  in  cardiac  cases  of  dropsy.  It  is  lethal 
in  the  proportion  of  V200  of  the  body-weight.  According  to 


438 


CLINIC  CHEMISTRY. 


Bouchard,  the  symptoms  of  so-called  uremia  may  be  ascribed 
to  six  other  toxic  substances  in  addition  to  urea.  One  of  these 
is  a  my  otic;  another,  a  sialagogue;  a  third,  narcotic;  a  fourth 
depresses  temperature;  and  K  and  another  substance  are  con- 
vulsants.  Some  of  these  poisons  are  probably  pigments,  as  pass- 
ing through  charcoal  lessens  the  noxious  power  of  the  urine  by 
Y8.  Urinary  toxicity,  as  measured  by  intravenous  injections 


E_  * 


1.01 


Q 


Cf 


Fig.  54.—  Doremus  Ureometer. 

into  animals,  is  usually  heightened  in  infectious  diseases;  it  is 
diminished  in  kidney  diseases  and  is  quite  absent  during  uremia. 
The  normal  daily  quantity  of  urea  excreted  by  way  of  the 
urine  is  from  17  to  40  gm.  (usually  30  to  40  gm.),  or  15  to  32 
mg.  per  kg.  of  body-weight.  One-tenth  less  is  excreted  by 
women  than  by  men  of  the  same  weight.  Children,  after  the 
first  month,  have  an  output  relatively  double.  In  old  age  the 
proportion  is  reduced  by  half.  Large  persons  obviously  pass 
out  more  urea  than  small  ones.  The  average  percentage  of 


URINE.  439 

urea  for  adult  males  is  about  2  per  cent.  The  maximum  ratio 
is  six  hours  after  meals;  the  minimum  in  the  early  morning. 

The  urea  of  the  urine  is  increased  by  proteid  diet  espe- 
cially,, and  to  a  less  extent  by  muscular  exertion,  caffein,  opiates, 
electricity,  the  copious  ingestion  of  liquids,  alkaline  chlorids, 
mineral  acids,  and  a  close  atmosphere.  It  is  decreased  by  a 
milk  and  vegetable  diet,  and  to  a  less  degree  by  fasting,  loose 
bowels,  free  sweating,  menstruation,  alcohol,  iron,  lead,  mer- 
cury, or  digitalis. 

Pathologically  an  excess  of  urea  is  noted  in  acute  febrile 
and  inflammatory  diseases,  diabetes  mellitus  and  insipidus, 
dyspneic  conditions,  malaria  and  severe  blood  diseases,  minor 
chorea,  paralysis  agitans,  some  gastro-intestinal  disorders,  and 
in  belladonna  or  phosphorus  poisoning. 

A  deficient  quantity  of  urea  is  a  most  important  feature 
of  all  forms  of  Bright's  disease,  and  is  due  chiefly  here  to  im- 
paired nutrition  of  the  renal  cells.  A  decrease  is  also  observed 
in  cachexia  and  malnutrition  (more  in  gastric  cancer  than  in 
simple  inanition);  hepatic  carcinoma,  cirrhosis,  and  acute  yel- 
low atrophy;  acute  gout  and  chronic  rheumatism;  osteoma- 
lacia;  chronic  lead  poisoning;  diarrhea,  cholera,  and  excessive 
sudation;  simple  anemia  and  leukemia;  melancholia,  imbecil- 
ity, catalepsy,  hysteria;  Addison's  and  Weil's  disease;  leprosy, 
pemphigus,  impetigo. 

Detection  of  Urea. — Evaporate  a  few  drops  of  urine  nearly  to  dry- 
ness  with  a  drop  of  HN03.  Large,  colorless,  rhombic  or  hexagonal  plates 
of  urea  nitrate  may  be  seen  with  the  microscope. 

Estimation  of  Urea. — The  most  practical  methods  for  clinic  pur- 
poses depend  on  decomposition  of  urea  by  freshly  made  sodium  hypo- 
bromite  in  a  strongly  alkaline  solution. 

N2H4CO  +  SNaBrO  =  3NaBr  +  CO2  +  2H2O  +  2N 

The  CO2  is  absorbed  by  the  alkali,  and  the  N  collects  at  the  closed  top 
of  the  instrument. 

The  ureometer  of  Doremus  is  very  simple  and  convenient.  It  is 
half-filled  with  40-per-cent.  NaHO  solution,  1  c.c.  of  Br  introduced,  and 
after  this  the  instrument  is  filled  by  adding  more  water.  One  c.c.  of  the 
urine  is  now  carefully  introduced  under  the  long  arm  by  means  of  the 
pipet.  The  bubbles  of  N  collect  at  the  top,  and  when  effervescence  ceases 
the  percentage  of  urea  can  be  read  off  directly  from  the  graduations  on 
the  cylinder  (best  immersed  in  water  to  the  level  of  the  column  of  fluid). 
One  c.c.  of  N  represents  0.0027  gm.  urea. 

Kjeldahl's  Method  to  Determine  Total  Nitrogen. — The  rationale 
of  this  method  is  as  follows:  On  prolonged  heating  of  any  nitrogenous 
substance  with  H2S04  all  the  N  is  converted  into  (NH4)2S04,  which  is 
decomposed  on  distilling  with  an  alkali,  and  the  liberated  NH3  collected 
in  a  known  quantity  of  an  n/]0  acid.  The  amount  of  the  acid  neutralized 
by  the  NH3  is  estimated  by  titrating  with  n/10  alkali,  and  from  this  re- 
sult the  amount  of  N  calculated. 


440 


CLINIC  CHEMISTRY. 


Place  5  c.c.  of  urine  in  a  250  c.c.  Kjeldahl  flask;  add  15  c.c.  H2S04 
and  Y4  gm.  powdered  CuS04;  heat  on  a  wire  gauze  under  the  hood  till 
foaming  ceases;  then  add  10  gm.  powdered  K2S04  and  continue  boiling 
gently  till  the  liquid  is  a  light  green.  Then  add  a  few  grains  of  powdered 
K2Mn2O8  and  heat  again  till  fluid  is  light  green.  Allow  to  cool;  transfer 
to  a  liter  Erlenmeyer  flask,  adding  the  washings  from  the  digestion  flask; 
dilute  to  about  500  c.c.,  and  add  a  few  grains  of  powdered  talc. 

Insert  a  doubly-perforated  rubber  stopper  with  a  Reitmaier  bulb 
and  a  thistle-tube  reaching  nearly  to  the  bottom  of  the  flask.  A  long 
strip  of  red  litmus-paper  should  be  hung  from  the  neck  of  the  flask 


Fig,  55.— Kjeldahl  Method, 


down  into  the  liquid.  Connect  the  upper  end  of  the  bulb  with  a  con- 
denser and  a  500  c.c.  receiving  flask  containing  50  c.c.  of  n/10  oxalic  acid. 
Pour  50  to  60  c.c.  of  50-per-cent.  NaHO  into  the  large  flask  and 
distil  over  about  200  c.c.  Then  replace  the  receiving  flask  by  another 
containing  10  c.c.  of  n/10  oxalic  acid  and  some  water,  and  distil  over 
100  c.c.  Now  add  a  few  drops  of  alcoholic  rosolic-acid  solution  and 
titrate  with  n/10  NaHO  to  a  deep-pink  color;  the  second,  or  check,  flask 
should  be  free  or  nearly  free  from  NH3.  A  blank  experiment  with  the 
reagents,  but  without  the  urine,  should  be  done  to  ascertain  the  amount 
of  N,  if  any  present  in  the  reagents,  and  the  result  subtracted  from  the 
total.  The  difference  between  the  number  of  c.c.  of  decinormal  alkali 
taken  and  that  left  after  neutralization  gives,  when  multiplied  by  0.0014 
(N  equivalent  factor ),  the  amount  of  N  in  5  c.c.  of  urine. 


URINE.  441 

URIC  ACID. 

The  alloxuric  bodies  are  derived  chiefly  from  the  cleavage 
of  nucleins  of  the  body-cells  and  of  ingested  nucleo-proteids. 
All  these  nucleins  or  purin  bodies  are  precipitated  by  ammo- 
niacal  silver-nitrate  solution.  The  nuclein  bases  predominate 
in  simple  decomposition,  while  oxidation  processes  lead  to  the 
formation  of  uric  acid,  which  normally  exceeds  the  bases  ten 
times  in  the  output  of  alloxuric  N,  and  may  generally  be  taken 
as  the  criterion  of  nuclein  metabolism.  In  gout,  however,  the 
lower  oxidation  products,  such  as  xanthin,  may  exceed  uric  acid. 
Although  urea  may  be  formed  artificially  by  oxidation  of  uric 
acid  and  many  other  organic  compounds,  there  is  no  proof  that 
in  the  metabolism  of  the  organism  uric  acid  represents  a  sub- 
oxidation  analog  of  urea,  or  that  the  quantity  of  these  two 
substances  bears  any  necessary  relation  to  each  other.  The 
normal  daily  output  of  uric  acid  is  0.4  to  0.8  gm.;  of  xanthin, 
0.03  to  0.05  gm. 

The  pure  uric  acid  is  crystalline,  and  requires  16,000  parts 
of  cold  or  1600  parts  of  boiling  water  to  dissolve  it.  It  is  also 
soluble  in  alkaline  hydrate's,  carbonates,  and  phosphates.  It 
appears  to  be  formed  chiefly  in  the  liver  and  spleen  by  the 
synthesis  of  ammonia  and  lactic  acid.  It  exists  in  the  urine 
normally  as  urates,  which  are  either  neutral  or  acid,  the  latter 
class  being  subdivided  into  monacid  or  biurates,  and  triacid  or 
quadriurates  or  tetraurates.  The  normal  salts  are  readily  sol- 
uble; acid  urates  much  less  so,  especially  in  cold  water.  A 
brick-dust  deposit  of  acid  urates  is  commonly  observed  in  acid 
concentrated  urine,  especially  when  chilled. 

The  daily  excretion  of  uric  acid  is  increased  by  excess  of 
proteid  foods,  especially  meat-broths,  glands,  and  young  flesh; 
also  by  tea,  coffee,  cocoa,  fats,  alcoholics,  and  the  administra- 
tion of  thymus  gland  or  nucleins.  Its  elimination  is  aided  by 
the  administration  of  sodium  salicylate,  disodic  phosphate, 
colchicum,  corrosive  sublimate,  or  euonymin. 

The  uric  acid  of  the  urine  is  decreased  by  a  milk  and 
vegetable  diet;  also  by  KI,  large  doses  of  quinin,  coal-tar  anti- 
pyretics, NaCl,  alkalies,  and  the  habitual  ingestion  of  large 
quantities  of  water.  Lithium  salts  and  mineral  acids  diminish 
the  elimination  of  uric  acid  temporarily  by  rendering  it  less 
soluble  in  the  blood;  the  relief  they  give  is  transient  and  they 
eventually  do  harm. 

The  most  marked  increase  of  uric  acid  occurs  in  leukemia: 
up  to  even  8  gm.  daily.  An  excess  is  also  noted  in  acute  fevers 
and  inflammations,  dyspneic  disorders,  splenic  diseases,  malaria, 
scurvy,  pernicious  anemia,  diabetes,  rachitis,  abdominal  tumors, 


442  CLINIC  CHEMISTRY. 

cancer  and  cirrhosis  of  the  liver,  migraine,  petit  mal,  neuras- 
thenia, chorea,  and  frequently  in  dyspeptic  disturbances.  In 
gout  uric  acid  is  diminished  before  and  during  the  paroxysms, 
and  greatly  increased  just  after. 

An  absolute  decrease  of  uric  acid  is  met  with  in  chronic 
arthritis,  chronic  lead  poisoning,  progressive  muscular  atrophy, 
chlorosis  and  simple  anemias,  usually  in  diabetes,  and  in  most 
forms  of  advanced  kidney  disease  and  chronic  disorders  gener- 
ally. 

Murexid  Test. — Evaporate  a  small  portion  of  the  urate  or  uric  acid 
sediment  to  dryness  in  a  porcelain  dish,  add  a  drop  or  two  of  HNO3  to 
dissolve  the  residue,  stir  with  a  glass  rod,  and  evaporate  slowly  to  dry- 
ness.  Allow  to  cool  and  add  1  or  2  drops  of  NH4OH,  getting  a  beautiful 
purplish  coloration  due  to  murexid  or  ammonium  purpurate,  C8H4.NH4.- 
N5O6.  On  adding  now  a  drop  of  NaHO  the  color  changes  to  reddish  blue 
and  disappears  on  heating.  The  test  can  be  rendered  more  delicate  by 
holding  a  dish  of  urine  and  acid  over  another  dish  in  which  a  dry  NH4 
salt  is  volatilized. 

Gravimetric  Estimation  (Heintz). — This  simple,  but  not  very  ac- 
curate, test  is  made  by  adding  to  200  c.c.  of  filtered  urine,  free  from 
albumin,  10  c.c.  of  HC1,  letting  stand  in  a  cool  place  for  twenty-four 
hours,  collecting  the  precipitated  uric  acid  crystals  on  a  dried  and  tared 
filter-paper,  washing  once  or  twice  with  cold  distilled  water,  drying  at 
100°  C.,  and  weighing. 

Volumetric  Method  (Hopkins).— This  depends  on  converting  all 
the  uric  acid  and  urates  into  ammonium  urate,  which  is  decomposed  by 
HC1,  and  the  separated  uric  acid  estimated  by  titration  with  n/^  KL,Mn208 
(standardized  each  time  against  hot  decinormal  oxalic  acid  containing 
a  little  H2SOJ,  each  c.c.  of  which  is  equivalent  to  0.00375  gm.  of  uric 
acid. 

Saturate  100  c.c.  of  urine  with  NH4C1  (about  35  gm.  usually  neces- 
sary), let  stand  for  two  hours  or  longer  with  occasional  agitation,  filter, 
and  wash  ppt.  three  or  four  times  with  saturated  solution  of  NH4C1. 
Then  wash  off  the  pptd.  urate  with  a  jet  of  hot  distilled  water  into  a 
small  beaker,  and  heat  just  to  boiling  with  excess  of  HC1.  Cool  and  let 
stand  for  at  least  two  hours  to  allow  uric  acid  to  separate  completely; 
filter  and  wash  crystals  with  cold  distilled  water. 

Now  wash  the  uric  acid  off  the  filter  with  hot  distilled  water,  add 
Na2CO3,  warm  until  the  acid  is  dissolved,  and  make  up  solution  to  100 
c.c.  Transfer  to  a  flask,  mix  with  20  c.c.  of  concentrated  H2S04,  and 
titrate  at  once  with  the  n/^  K2Mn208,  which  should  be  added  slowly 
toward  the  end  of  the  reaction,  as  shown  by  a  transient  pink  coloration. 
To  the  final  result,  calculated  in  mg.,  1  mg.  should  be  added  for  each 
15  e.c.  of  fluid  in  the  last  filtrate  (need  never  be  more  than  20  or  30  c.c.), 
not  taking  the  washings  into  account. 

When  there  is  an  abundant  deposit  of  phosphates,  these  should  be 
filtered  off  after  complete  pptn.  by  heat.  The  presence  of  albumin  makes 
it  necessary  to  continue  digestion  with  HC1  longer  in  order  to  form  the 
soluble  acid  albumin.  If  the  urine  contains  much  pigment,  this  should 
be  removed  from  the  urate  ppt.  by  treating  thoroughly  with  alcohol,  and 
after  acidulating  heating  the  filtrate  gradually  to  boiling  and  digest  for 
some  time  on  a  water-bath,  and  then  washing  the  separated  crystals 
thoroughly. 


URINE.  443 

Centrifugal  Estimation  (Cook). — To  10  c.c.  of  urine  add  1  gm.  of 
Na2C03  and  1  c.c.  of  NH4OH.  Shake  till  the  carbonate  is  dissolved, 
centrifugate  earthy  phosphates,  and  pour  off  clear  liquid  into  another 
tube.  Add  2  c.c.  of  NH4OH  and  1  c.c.  of  ammoniated  AgN03  (dram  to 
ounce),  and  separate  silver  urate  as  gelatinous  urate,  centrifugating 
until  the  reading  is  constant.  One-tenth  c.c.  of  ppt.  represents  0.00176 
gm.  of  uric  acid. 

This  method  is  accurate  and  very  convenient.  In  addition  to  uric 
acid  it  ppts.  the  other  alloxuric  bodies,  particularly  the  xanthins.  To 
separate  the  latter,  after  getting  the  centrifugal  sediment  as  above, 
transfer  it  to  a  smooth  filter  and  wash  with  water  till  free  of  silver. 
The  filter  is  now  punctured  and  the  ppt.  washed  into  a  liter-flask  with 
600  to  800  c.c.  of  water.  The  contents  of  the  flask  are  acidulated  with 
a  few  drops  of  HC1  and  then  saturated  with  washed  H2S,  boiled  and 
quickly  filtered  through  a  small  filter,  and  the  Ag2J3  ppt.  washed  with 
boiling  water.  The  filtrate  is  evaporated  over  a  naked  flame  and  then 
to  dryness  on  the  water-bath.  The  residue  of  alloxuric  bodies  is  now 
treated  with  25  c.c.  of  1  to  30  H2S04,  heated  to  boiling  over  a  small 
flame,  and  let  stand  for  twenty  hours.  The  acid  dissolves  the  purin 
bases,  but  not  uric  acid:  these  are  now  separated  by  filtration  and 
washing  with  the  diluted  H2SO4.  The  filtrate,  containing  the  xanthins, 
may  be  tested  by  the  centrifugal  method  given  above,  or  by  pptg.  with 
ammoniacal  AgN03,  incinerating,  dissolving  in  a  little  HNO3,  and  ti- 
trating with  standard  NH4CNS  solution.  One  part  Ag  is  equivalent  to 
0.7381  gm.  of  alloxuric  bases  calculated  as  xanthin. 


HIPPTJRIC   ACID. 

Hippuric  acid,  C9H9N03,  is  normally  present  in  large 
amounts  in  the  urine  of  herbivora;  in  the  autophagic  condition 
of  inanition,  however,  uric  acid  appears.  It  is  a  crystalline  sub- 
stance averaging  in  daily  amount  in  the  human  urine  from  0.5 
to  1  gm.,  and  is  of  no  present  practical  interest.  It  is  increased 
by  vegetable  foods  containing  benzoic  acid,  such  as  cranberries, 
bilberries,  prunes,  greengages,  etc.,  and  by  the  administration 
of  benzoic  or  cinnamic  acid  or  toluol.  Pathologically  an  excess 
is  noted  in  acute  febrile  diseases,  chorea,  diabetes  mellitus,  and 
hepatic  disorders.  It  is  said  to  be  diminished  in  amyloid  de- 
generation of  the  kidney  and  absent  in  acute  and  chronic  paren- 
chymatous  nephritis. 

Detection. — Evaporate  urine  to  dryness  with  HNO3,  heat  residue 
in  a  test-tube,  and  note  odor  of  bitter  almonds,  due  to  formation  of 
nitrobenzol. 

CREATININ. 

This  is  £reatin  (C4H9N302)  minus  water.  It  occurs  in 
about  the  same  quantity  as  uric  acid  and  is  probably  derived 
from  meat  food.  In  alkaline  urine  it  is  replaced  by  creatin. 

Detection.— ZnCl?  gives  a  crystalline  ppt.  [(C4H7N30)2.ZnCl2]  of 
fine  needles  grouped  in  rosettes  or  sheaves.  This  test  may  be  used 
quantitatively. 


444  CLINIC  CHEMISTRY. 


ALLANTOIN. 

Allantoin,  C4H6N40,  is  found  only  in  a  trace  except  in  the 
urine  of  the  newborn.  It  is  increased  by  a  meat  diet  and  the 
administration  of  tannic  acid. 


AMMONIA. 

This  amounts  in  the  urine  to  0.5  to  0.8  gm.  daily.  An 
absolute  increase  is  noted  after  fermentation  of  the  urine,  in 
fevers  generally,  and  in  diseases  of  the  liver.  It  is  sometimes 
greatly  increased  in  carcinoma.  A  marked  increase  (1  gm.  or 
more  per  diem)  in  diabetes  forebodes  coma. 


ENZYMES. 

Variable  traces  of  pepsin  and  rennin  are  found  in  the 
urine,  the  maximum  being  four  to  six  hours  after  meals.  The 
ferments  are  said  to  be  diminished  or  absent  in  gastric  car- 
cinoma. 

CALCIUM   OXALATE. 

About  a  decigram  of  oxalic  acid  is  excreted  daily  in  normal 
urine,  chiefly  as  CaC204.  When  in  excess  this  is  pptd.  as  octa- 
hedral or  dumb-bell  crystals.  An  excess  usually  signifies  -defi- 
cient oxidation.  On  the  urine  standing  the  crystals  may  form 
from  urates  and  uric  acid. 

The  daily  output  of  CaC204  is  increased  by  tomatoes,  beets, 
rhubarb,  spinach,  sorrel,  cauliflower,  celery,  carrots,  beans, 
asparagus,  apples,  pears,  grapes,  pease,  cabbage,  claret,  and 
effervescent  drinks.*  An  excess  is  also  observed  in  defective 
digestion  of  fats  and  carbohydrates  (flatulent  and  nervous  dys- 
pepsia); in  malassimilation,  the  gouty  habit,  cancer,  tubercu- 
losis, diabetes  mellitus,  and  catarrhal  jaundice.  Oxaluria,  mani- 
fested by  vesic  tenesmus  and  pain  across  the  back,  sometimes 
extending  down  the  thighs  or  into  the  testicles,  often  accom- 
panies spermatorrhea,  sexual  neurasthenia,  and  functional  mel- 
ancholia or  hypochondriasis. 

BILE-SALTS. 

The  biliary  acids  are  present  normally  in  the  urine  to  the 
extent  of  0.12  gm.  daily.  They  are  increased  by  active  mus- 
cular exercise  and  diminished  after  meals.  Pathologically  an 
increase  is  noted  in  most  blood  diseases  and  particularly  in  liver 
disorders,  especially  the  decline  of  bilious  attacks.  A  decided 


URINE.  445 

and  persistent  decrease  takes  place  in  chronic  interstitial  ne- 
phritis. 

Estimation. — Oliver's  test  solution  consists  of  1/2  dr.  of  powdered 
pepton,  4  gr.  of  salicylic  acid,  a/2  dr.  of  acetic  acid  and  8  oz.  distilled  water, 
repeatedly  filtered  till  quite  transparent.  It  reacts  to  1  part  iii  10,000 
or  more.  To  make  the  test  the  urine  must  be  made  perfectly  clear  (by 
filtering  or  shaking  with  magnesium  fluid),  be  rendered  acid,  and  have 
its  sp.  gr.  reduced  to  1.008.  Twenty  m.  of  the  urine  are  added  to  60  m. 
of  the  test  solution.  If  bile-acids  are  present  in  normal  quantity  no 
immediate  reaction  occurs,  but  in  a  few  minutes  the  urine  becomes 
faintly  opalescent.  An  excess  is  indicated  by  the  immediate  appearance 
of  a  distinct  milkiness.  The  test  can  be  made  approximately  quanti- 
tative by  mixing  equal  parts  of  the  test  solution  and  of  normal  urine 
as  a  standard.  A  urine,  for  instance,  of  which  10  m.  with  60  of  the  test 
solution  produces  the  same  degree  of  opacity  as  the  normal  standard 
mentioned,  contains  six  times  as  much  bile-salts  as  normally. 

MUCIN. 

A  small  quantity  of  mucin  is  present  in  all  urines,  espe- 
cially that  of  women,  from  vaginal  admixture.  An  excess  shows 
irritation  or  inflammation  of  the  genito-urinary  tract  below  the 
kidneys,  by  abnormal  products,  concentrated  urine  or  urinary 
crystals,  or  following  anesthesia.  Mucinuria  often  precedes 
albuminuria  in  fevers.  Excessive  amounts,  with  abundance  of 
epithelium,  are  encountered  in  cystitis,  making  the  urine  slimy 
and  viscid. 

Detection. — Mucin  is  pptd.  in  light-colored  threads  by  vegetable 
acids  or  quite  dilute  mineral  acids.  The  test  is  made  more  delicate  by 
treating  with  alcohol  for  several  hours,  and  acidifying  the  filtrate  with 
acetic  acid. 

COLORING  MATTERS. 

These  are,  in  general,  best  distinguished  by  the  spectro- 
scope. Normal  urobilin,  C32H40N407,  and  its  impure  derivative, 
urochrom,  are  the  chief  coloring  matters  of  the  urine,  amount- 
ing to  about  4  gm.  daily.  They  may  originate  either  from  bile 
or  blood-pigment,  but  whether  by  oxidation  or  reduction  is  un- 
settled. They  are  somewhat  resinous  and  not  very  soluble; 
hence  they  are  removed  to  some  extent  by  simple  nitration. 
They  are  increased  whenever  destruction  of  red  corpuscles  is 
augmented,  as  in  fevers  generally,  internal  hemorrhages,  heart 
and  liver  diseases,  typhoid  and  septic  conditions,  scurvy,  hemo- 
philia, and  progressive  pernicious  anemia.  A  decrease  is  noted 
in  diabetes,  chronic  nephritis,  anemia,  chlorosis,  nervous  dis- 
orders, extra-uterine  pregnancy,  and  convalescence.  They  may 
be  absent  in  total  obstruction  of  bile. 

Detection  of  Urobilin. — Acidulate  10  c.c.  of  urine  with  a  few  drops 
of  HC1,  shake  with  half  as  much  amyl  alcohol,  and  add  a  few  drops  of 


44G  CLINIC  CHEMISTRY. 

1-per-cent.  alcoholic  solution  of  ZnCl2  rendered  strongly,  alkaline  with 
NH4OH.     A  beautiful  green  fluorescence  appears. 

Detection  of  Urochrom. — Ppt.  from  solution  with  ammonium  sul- 
phate and  decompose  with  an  acid,  yielding  a  brown  or  black  substance. 

Uroerythrin  (purpurin,  rosacic  acid)  is  an  amorphous, 
brick-red,  iron-free  substance,  usually  in  combination  with  uric 
acid.  The  pink  or  reddish  color  of  urates  in  deposits  is  due 
to  uroerythrin.  Its  solution  is  colored  dark  green  by  an  alka- 
line hydrate.  An  increase  of  this  substance  is  observed  in  ma- 
larial fever,  pneumonia,  erysipelas,  and  hepatic  cirrhosis  or 
cancer. 

Uroroseinogen  is  a  chromogen  which  develops  a  rose-red 
color  on  addition  of  a  mineral  acid.  It  is  increased  by  vegetable 
diet  and  in  conditions  of  malnutrition  generally. 

GLYCEROPHOSPHORIC   ACID. 

C3H9P06  is  derived  from  nervous  tissue  and  amounts  nor- 
mally to  20  mg.  daily.  It  is  increased  in  nervous  and  febrile 
disorders  and  after  chloroform  anesthesia. 


ABNORMAL  CONDITIONS. 

ALBUMINURIA  AND   GLOBULINURIA. 

True  or  renal  albuminuria  is  persistent  and  usually  consid- 
erable in  amount.  It  is  nearly  always  accompanied  by  casts, 
anemia,  dropsy,  or  uremia.  The  access  of  the  circulating  pro- 
teins to  the  urine  is  attributable  chiefly  to  impaired  nutrition 
of  the  renal  cells,  due,  in  the  first  place,  usually  to  chemic  irri- 
tants (lead,  alcohol)  or  toxins.  Under  this  division  come  acute 
and  chronic  parenchymatous  nephritis  (large  amount),  chronic 
interstitial  nephritis  (small  amount;  sometimes  absent),  active 
and  passive  renal  congestion  (small  quantity),  amyloid  de- 
generation (globulin  sometimes  exceeds  albumin),  malignant 
growths  (small  or  moderate  amount),  renal  cysts  (5  to  30  per 
cent,  by  volume),  movable  and  floating  kidney  and  hydrone- 
phrosis  (small  amount  in  all),  and  the  passage  of  excess  of 
uric  acid  or  calcium  oxalate  crystals  or  urates. 

Functional,  or  "physiologic,"  albuminuria  is  small  in 
amount,  transitory,  and  intermittent,  in  apparently  healthy, 
but  often  neurotic,  persons.  It  is  rarely  accompanied  by  hyaline 
casts.  Common  causes  of  this  form  are  cold  baths;  severe  men- 
tal or  muscular  exertion  (bicycling);  violent  emotions;  eating 
eggs,  cheese,  or  meat  to  excess;  and  following  anesthesia.  Con- 
centrated urine  with  or  without  a  deposit  of  uric  acid  or  calcium 


URINE.  447 

oxalate  is  frequently  accompanied  by  a  little  albumin  and  a  few 
cylindroids.  In  the  cyclic,  periodic,  or  postural,  variety  of  albu- 
minuria  the  albumin  disappears  from  the  urine  at  night  or 
during  rest,  recurring  after  meals  or  exercise.  It  is  most  often 
observed  in  male  adolescents,  and  is  attributed  to  renal  conges- 
tion due  to  the  erect  posture.  A  trace  of  albumin  is  present 
for  the  first  few  days  after  birth,  and  in  persons  dead  for  some 
hours  any  retained  urine  may  contain  albumin  from  the  macer- 
ated bladder-walls. 

Albuminuria  of  nervous  origin  is  usually  slight,  and  may 
be  temporary  or  permanent.  It  is  observed  from  high  blood- 
pressure  after  epileptic  attacks;  also  in  surgical  shock,  con- 
cussion of  the  brain,  acute  intestinal  obstruction,  mania,  delir- 
ium tremens,  tetanus,  exophthalmic  goiter,  and  even  occasion- 
ally in  migraine. 

The  circulatory  form  of  albuminuria  is  usually  slight  in 
amount,  and  is  most  commonly  due  to  passive  congestion  of  the 
kidneys,  as  in  organic  heart  disease  and  great  weakness,  or 
hepatic  cirrhosis  or  emphysema.  The  same  type  is  exemplified 
in  compression  of  the  renal  veins  by  tumors  or  the  pregnant 
uterus.  In  renal  embolism  the  albuminuria  is  sudden  and  pro- 
nounced, with  hematuria,  disappearing  gradually  in  a  few  days. 

Obstructive  albuminuria  is  accompanied  by  temporary  or 
permanent  oliguria.  A  common  cause  of  this  type  is  impacted 
calculus,  which  is  manifested  further  by  aching  pain  in  the 
loin,  crystals  and  concretions,  and  bloody  urine.  Another  cause 
is  twist  of  the  ureter  by  a  displaced  kidney,  in  which  there  is 
also  severe  paroxysmal  pain  like  renal  colic.  Other  causes  of 
this  nature  are  peritonitic  adhesions,  pressure  on  a  ureter  by  a 
tumor  or  the  pregnant  uterus,  and  the  uric-acid  infarcts  of 
infants. 

The  hemic  type  of  albuminuria  depends  on  abnormal  blood- 
changes,  and,  in  addition  to  all  the  blood  diseases,  includes 
obesity,  diabetes  mellitus  (irritation  of  sugar),  gout,  syphilis, 
nutrient  enemata  and  intestinal  autointoxication  (disappears 
rapidly  under  intestinal  antiseptics),  and  severe  stomach  dis- 
eases. 

Toxic  albuminuria  represents  the  local  irritant  action  of 
chemicals  in  the  blood  on  the  kidneys;  it  is  often  attended  by 
bloody  or  discolored  urine.  The  most  common  agents  giving 
rise  to  this  symptom  are  turpentine,  cantharis,  saltpeter,  car- 
bolic and  salicylic  acids,  tar,  creasote,  iodin,  lead,  arsenic,  mer- 
cury, alcohol,  phosphorus,  ether,  chloroform,  morphin,  mineral 
acids,  ammonia,  and  carbon  monoxid. 

In  the  febrile  type  of  albuminuria  the  hemic,  toxic  (toxins), 


448  CLINIC  CHEMISTRY. 

and  circulatory  forms  are  combined.  We  find  albuminuria  in 
nearly  all  acute  inflammations  and  infectious  fevers,  especially 
scarlatina,  in  which  albuminuria  is  post-febrile  and  due  to  acute 
nephritis.  In  diphtheria  there  is  a  nephritis  during  the  attack. 
False  or  adventitious  albuminuria  is  due  to  the  presence  of 
pus  or  blood  from  any  part  of  the  urinary  tract,  or  to  semen  or 
vaginal  discharges.  In  pyelitis  there  is  often  considerable  albu- 
min (more  than  is  accounted  for  by  the  pus  in  the  urine):  a 
distinction  from  cystitis.  Albumin  from  leucorrhea  is  readily 
excluded  by  catheterization. 

Qualitative  Tests  for  Albumin  and  Globulin. 

Roberta's  Contact  Test. — Fill  a  clean  wineglass  one-half  with  clear 
or  filtered  urine.  Incline  the  glass  and  slide  under  the  urine  about  half 
as  much  of  the  nitric  magnesian  fluid  (1  part  of  strong  HN03,  5  parts 
of  saturated  MgSO4  solution),  and  let  stand,  if  need  be,  for  fifteen 
minutes.  If  albumin  is  present  (1  to  50,000  or  less)  a  white  band  will 
appear  exactly  at  the  junction  of  acid  and  urine.  This  zone  is  sharply 
outlined  above  and  below,  and  appears  best  against  a  dark  background. 
The  width  of  the  band  depends  mostly  upon  the  degree  of  admixture  of 
the  two  fluids,  and  is  not  so  much  a  criterion  of  quantity  as  is  its 
density.  When  there  is  a  relative  excess  of  uric  acid  a  light-colored 
ring  is  to  be  seen  at  a  little  distance  above  the  line  of  junction.  Excess 
of  mucus  is  manifested  by  a  diffuse  irregular  cloudiness  in  the  upper 
part  of  the  urine.  Various  colorings  (blue  or  red  from  indican;  red 
from  uroroseinogen;  red-brown  from  iodids)  are  often  to  be  seen  about 
the  line  of  contact.  The  test  is  one  of  the  best  for  routine  examina- 
tions, though  it  also  gives  a  white  zone  with  alkaloids,  resinous  medi- 
cines, and  albumoses  (cleared  by  heat). 

Heat  Test. — To  a  half-filled,  wide  test-tube  of  urine  add  a  drop  of 
10-per-cent.  acetic  acid;  if  alkaline,  add  2  or  3  drops  until  faintly  acid. 
HNO3  should  not  be  used,  since  it  would  form  soluble  acid  albumin. 
The  addition  of  one-fourth  as  much  saturated  NaCl  solution  aids  con- 
siderably in  pptg.  globulin  and  keeping  mucin  in  solution.  Heat  the 
upper  half  of  the  urine  to  boiling  (albumin  coagulates  about  75°),  and 
note  white  ppt.  if  it  appears.  When  due  to  earthy  phosphates  this 
opacity  clears  up  on  adding  a  few  more  drops  of  acetic  acid,  whereas 
the  albumin  opacity  remains  and  may  become  denser.  The  cloudiness 
of  the  upper  part  as  compared  with  the  lower  is  best  discerned  against 
a  dark  background.  This  is  the  oldest  test  for  albumin,  and  quite 
certain. 

Ferrocyanid  Test. — Mix  1  part  50-per-cent.  acetic  acid  and  2  parts 
10-per-cent.  K4FeCy6  solution  in  a  wineglass,  and  carefully  overlay  with 
the  clear  acid  urine.  A  sharply-defined  white  zone  at  point  of  contact 
shows  the  presence  of  albumin.  This  reagent  does  not  ppt.  peptons, 
alkaloids,  or  phosphates,  but  may  ppt.  acid  urates  (it  may  then  be 
cleared  by  heat). 

Spiegler's  Contact  Test  for  Albumin. — The  reagent  contains  40 
parts  of  mercuric  chlorid,  20  parts  of  tartaric  acid,  100  parts  of  white 
sugar,  and  1000  parts  of  distilled  water.  If  the  ring  is  due  to  mucin 
a  drop  of  HC1  clears.  The  test  is  said  to  react  with  1  part  of  albumin 
in  150,000. 


URINE. 


449 


Quantitative  Tests  for  Albumin. 

Purdy's  Centrifugal  Method. — To  10  c.c.  of  urine  add  3  c.c.  of 
10-per-cent.  solution  of  potassium  ferrocyanid  and  2  c.c.  of  50-per-cent. 
acetic  acid.  Set  aside  for  10  minutes,  then  revolve  for  3  minutes  at  a 
uniform  rate  of  1500  revolutions  per  minute.  The  weight  percentage  is 
almost  exactly  one-fiftieth  of  the  bulk  percentage. 

Esbach  Method.  —  A  graduated  al- 
buminometer  and  a  standard  solution  are 
employed.  The  solution  consists  of  10 
gm.  of  picric  acid,  20  gm.  of  citric  acid, 
and  distilled  water  to  a  liter.  The  al- 
buminometer  tube  is  filled  with  urine  to 
the  letter  u,  then  the  test  solution  is 
added  to  R,  and  the  two  fluids  well 
mixed.  The  tube  is  let  stand  for  twenty- 
four  hours,  when  the  depth  of  the  sedi- 
ment will  show  the  amount  of  albumin 
in  gm.  per  liter.  The  test  is  simple,  but 
only  approximate  in  its  results,  and  the 
solution  reacts  with  most  other  proteins 
as  well  as  albumin. 

Gravimetric  Method. — This  consists 
simply  in  acidulating  100  c.c.  of  the  urine 
with  acetic  acid,  filtering,  boiling  for  a 
half-minute,  filtering,  drying  until  the 
weight  of  the  filter  and  contents  is  con- 
stant, and  then  weighing.  The  test  is 
easy,  but  consumes  considerable  time. 


ALBUMOSURIA. 

Albumoses  were  till  recently 
confounded  with  peptons  in  the 
urine;  so  that  at  present  the  clinic 
significance  of  albumosuria  is  very 
indefinite.  The  condition  has  been 
noted  in  sarcoma  of  the  ribs,  osteo- 
malacia,  tertiary  syphilis,  hemiple- 
gia,  carcinoma,  diphtheria,  double 
pneumonia,  multiple  myelomata, 
and  muscular  and  renal  atrophy. 
The  reactions  of  the  different  pro- 
teoses  are  shown  in  the  table  on 
page  450. 


u 

J 


Fig.  56.— Esbach's  Albuminometer. 


PEPTONURIA. 


A  slight  amount  of  pepton  frequently  accompanies  albu- 
minuria.  A  considerable  quantity  is  generally  of  pyogenic 
origin  (suppurative  meningitis  or  appendicitis,  empyema,  pul- 


450 


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URINE.  451 

monary  tuberculosis,  etc.).  It  is  also  noted  during  resorption 
of  inflammatory  effusions,  as  in  pneumonia,  and  in  puerperal 
conditions,  intestinal  ulceration,  acute  infections,  toxic  condi- 
tions, and  cancer  of  the  liver. 

Detection. — To  separate  the  other  proteins,  if  present,  the  urine 
should  be  saturated  while  boiling  with  ammonium  sulphate  several 
times.  Peptons,  if  present,  may  then  be  pptd.  with  Tanret's  reagent 
(KI,  3.22  gm.;  HgCl2,  1.35  gm.;  H2O,  to  100  c.c.).  If  other  proteins  are 
not  present  peptons  may  be  pptd.  with  tannin  from  the  decanted  fluid 
after  pptg.  the  phosphates  in  the  centrifuge. 

FIBRINURIA. 

Without  accompanying  hematuria,  this  condition  is  seen 
only  in  chyluria  and  diphtheritic  inflammation  of  the  urinary 
passages.  Macroscopic  fibrinous  plugs  are  sometimes  found  in 
the  urine  of  pyelitis  and  ureteritis.  They  do  not  dissolve  in  hot 
water,  but  are  acted  on  readily  by  pepsin  and  dilute  HC1. 

GLYCOSTTRIA. 

The  presence  of  dextrose  (and  levulose)  in  the  urine  may 
be  classified  etiologically  as  artificial,  transitory,  and  diabetic. 
Artificial  glycosuria  is  produced  by  excess  of  carbohydrate  food, 
sweet  wines,  grapes,  and  confectionery;  also  by  thyroid  extract, 
and  in  chronic  lead  poisoning;  in  asphyxia;  and  in  poisoning 
by  phosphorus,  coal-gas,  ether  (inhalations),  curare,  HCN", 
H2S04,  strychnin,  Hg,  alcohol,  glycerin,  amyl  nitrite,  or  nitro- 
benzol.  Phloridzin  causes  glycosuria  through  the  action  of  this 
compound  on  the  kidneys. 

Slight  or  transient  glycosuria  is  noted  especially  in  fat 
elderly  men  and  women;  it  is  quasinormal,  and  is  due  to  a 
lowering  of  the  sugar-consuming  power  of  the  tissues.  In  other 
forms  of  non-diabetic  glycosuria  there  is  some  pathologic 
agency  affecting  the  glycogen-storing  function  of  the  liver, 
either  through  the  nervous  system,  the  stomach,  or  the  pan- 
creas or  by  directly  attacking  the  liver.  Gouty  glycosuria  is 
allied  to  the  alimentary  glycosuria  of  obesity.  Senile  glycosuria 
probably  depends  upon  the  greatly  reduced  capacity  of  the  aged 
body  to  consume  sugar.  The  form  which  follows  falls  and  in- 
juries or  nervous  lesions,  such  as  cerebral  apoplexy,  is  analogous 
to  the  sudden  discharge  of  accumulated  liver-glycogen,  caused 
by  experimental  lesions.  In  neurasthenia  the  glycogen-storing 
function  of  the  liver  is  permanently  depressed,  and  hyper- 
glycemia  and  diabetic  symptoms  may  ensue.  The  influence  of 
boils,  ulcers,  carbuncles,  and  many  acute  infections,  particu- 
larly influenza,  in  causing  glycosuria,  seems  to  depend  upon  the 


452  CLINIC  CHEMISTRY. 

toxins  produced  in  these  conditions,  and  it  usually  disappears 
along  with  the  fever. 

True  diabetic  glycosuria  is  persistent  and  usually  marked 
(up  to  10  per  cent.),  with  polyuria,  polydipsia,  polyphagia,  ema- 
ciation, and  pruritus.  It  is  often  accompanied  with  acetonuria, 
lipuria,  alkaptonuria,  and  oxybutyria.  The  most  marked  lesion 
known  to  be  capable  of  producing  diabetes  mellitus  is  wasting 
of  the  pancreas. 

Haines's  Test. — The  solution  consists  of  V2  dr.  of  pure  CuS04  dis- 
solved in  Y2  oz.  of  distilled  water;  1/2  oz.  pure  glycerin;  and  5  oz.  liquor 
potassse.  The  object  of  the  glycerin  is  to  prevent  the  precipitation  of 
the  copper  hydrate  that  is  formed.  Take  about  1  dr.  of  the  solution  in 
a  test-tube,  bring  it  to  a  boil,  and  add  6  to  8  drops  of  the  urine  while 
boiling.  If  glucose  is  present  a  yellow  or  red  ppt.  is  at  once  thrown 
down.  The  yellow  appears  first  and  is  due  to  reduction  to  cuprous 
hydrate;  the  red  sediment  is  cuprous  oxid.  The  boiling  should  not  be 
continued  longer  than  a  minute.,  since  uric  acid  and  other  substances 
will  reduce  copper  solutions  on  prolonged  heating  or  even  on  standing, 
giving  a  greenish  opacity.  The  grayish  cloud  of  earthy  phosphates  pptd. 
by  the  alkali  of  the  solution  should  not  be  mistaken  for  an  indication 
of  sugar.  This  is  the  best  qualitative  test  for  appreciable  amounts  of 
sugar  in  the  urine.  It  reacts  with  0.02  per  cent,  of  glucose. 

Fehling's  Test. — This  older  test  is  preferred  by  some,  though  it 
has  a  number  of  disadvantages.  The  solution  contains  34.639  gm.  of 
CuS04,  500  c.c.  of  NaHO  solution  (sp.  gr.,  1.12),  and  173  gm.  of  c.  p. 
Rochelle  salts  in  enough  distilled  water  to  make  a  liter.  Each  c.c.  of 
the  solution  is  exactly  decolorized  by  50  mg.  of  dextrose.  The  tartrate 
serves  the  same  purpose  as  the  glycerin  in  Haines's  test,  and  reduction 
takes  place  in  the  same  manner.  The  copper  solution  and  the  Rochelle- 
and-soda  solution  are  best  kept  separate  till  used,  mixing  equal  parts 
and  adding  the  urine  drop  by  drop  till  a  quantity  equal  to  the  mixed 
reagent  is  added.  Fehling's  solution  is  reduced  by  sugar,  uric  acid, 
creatin,  hippuric  acid,  carbolic  acid,  alkaloids,  etc. 

Bottger's  Test. — Bismuth  salts  are  likewise  reduced  to  the  metallic 
state  by  sugar  in  the  presence  of  alkali.  Add  to  the  urine  an  equal 
volume  of  liquor  potassae  and  then  a  little  subnitrate  of  bismuth.  On 
boiling  the  mixture  turns  gray  or  black  according  to  the  amount  of 
sugar  present.  .Traces  of  S  cause  a  similar  reaction;  hence  the  test  is 
not  applicable  in  albuminous  urine. 

Fermentation  Test. — Fill  the  saccharimeter  (an  inverted  test-tube 
will  answer)  with  the  urine  after  mixing  well  with  a  little  lump  of 
fresh  yeast.  Let  stand  in  a  warm  place  for  twenty-four  hours  and  notice 
whether  any  gas  (CO..,)  has  collected  in  the  upper  part  of  the  instrument. 
The  test  is  very  certain  when  there  is  considerable  glucose  present,  but 
unfortunately  does  not  show  any  result  with  less  than  0.5  per  cent,  of 
sugar,  owing  to  the  fact  that  water  absorbs  its  own  volume  of  CO2. 
Some  specimens  of  yeast  evolve  gas  spontaneously;  hence  it  is  well  to 
use  two  tubes,  one  as  a  control  experiment  with  water. 

To  utilize  the  fermentation  method  quantitatively  Roberts  directs 
to  fill  two  4-ounce  bottles  with  the  urine,  put  a  lump  of  yeast  in  one, 
cork  this  bottle  loosely  and  the  other  tightly,  and  keep  both  bottles  in 
a  warm  place  (80°  to  90°  F.)  for  twenty-four  hours.  Then  filter  both 
urines  and  take  their  sp.  gr.  The  difference  in  density  represents  chiefly 


PLATE   VI. 


CRYSTALS  OF  PHENYLGLUCOSAZONE. 

(After  v.  Jaksch.) 


URINE.  453 

the  CO2  given  off  from  fermentation  of  the  sugar,  and  each  degree  of  loss 
in  weight  is  equivalent  to  1  grain  of  glucose  to  the  ounce. 

Williamson's  Test.  —  A  delicate  (0.05  per  cent.)  and  accurate  test 
for  glycosuria,  and  one  that  does  not  react  with  the  common  reducing 
agents  of  normal  urine,  is  the  microchemic  test  with  phenyl-hydrazin, 
forming  beautiful  needle-shaped  crystals  of  phenyl-glucosazone,  which 
are  bright  .sulphur-yellow  in  color  and  are  arranged  singly  or  in  stellate 
groups  and  melt  at  204°  C. 


C8H1209  +  2C6H5.N2H3  =  CjgHaNA  +  2H20  +  H2 

In  an  ordinary  test-tube  place  1/2  inch  of  powdered  phenyl-hydrazin 
hydrochlorate,  then  solid  sodium  acetate  for  another  half-inch.  Half- 
fill  the  test-tube  with  urine  and  boil  for  two  minutes,  the  powders  pass- 
ing into  solution.  Let  cool  in  the  rack  and  examine  sediment  under 
rather  a  low  power. 

Quantitative  Estimation  of  Glucose.  —  The  best  method  for  med- 
ical purposes  is  that  of  Purdy.  His  solution  consists  of  4.752  gin.  of 
pure  CuSO4,  23.5  gm.  of  KHO,  350  c.c.  of  strong  NH4OH  (sp.  gr.,  0.9), 
38  c.c.  of  c.  p.  glycerin,  and  distilled  water  to  make  a  liter.  The  copper 
salt  and  glycerin  are  dissolved  separately  from  the  KHO,  then  mixed, 
and  after  cooling  the  ammonia  and  the  rest  of  the  water  added.  Thirty- 
five  c.c.  of  the  solution  are  reduced  on  boiling  by  exactly  0.02  gm.  of 
dextrose. 

Put  35  c.c.  of  the  test  solution  in  a  flask,  dilute  with  about  twice 
as  much  distilled  water,  and  bring  to  the  full  boil.  Fill  buret  to  the 
zero-mark  with  the  urine  to  be  tested,  which  is  run  down  slowly  into 
the  boiling  reagent  drop  by  drop  until  the  blue  color  begins  to  fade; 
then  still  more  slowly,  3  to  5  seconds  between  successive  drops,  until 
the  test  solution  is  left  quite  colorless  and  transparent.  The  per- 
centage of  sugar  in  the  urine  is  readily  calculated  by  dividing  0.02  by 
the  number  of  c.c.  of  urine  required  to  effect  decolorization.  The  test 
solution  is  stable  and  the  end-reaction  is  perfect. 

LACTOSTTRIA. 

Sugar  of  milk  is  occasionally  present  in  the  urine  of  women 
near  the  end  of  gestation  and  in  nursing  women,  especially  when 
there  is  obstruction  to  the  flow  of  milk,  as  in  mastitis.  It  is 
also  observed  in  nursing  infants  with  digestive  derangements. 

Detection.  —  If  the  urine  reduces  copper  solutions  feebly,  does  not 
ferment  with  yeast,  and  rotates  polarized  light  strongly  to  the  right, 
lactose  is  probably  present.  The  phenyl-hydrazin  test  also  yields  clus- 
ters of  yellow  needles  of  phenyl-lactosazone. 

INOSITTJRIA. 

Inosite  is  often  present  in  the  urine  in  diabetic  conditions, 
sometimes  taking  the  place  of  glycosuria.  It  has  also  been 
noted  in  nephritis,  typhus,  phthisis,  syphilis,  and  lesions  of  the 
•medulla. 

Detection.  —  Evaporate  with  concentrated  HN03  nearly  to  dryness 
on  a  Pt  dish;  moisten  residue  with  a  few  drops  of  NH4OH  and  CaCl2 


454  CLINIC  CHEMISTRY. 

solution;  then  evaporate  again  to  dryness.     A  vivid  rose-red  color  ap- 
pears with  even  1  mg.  of  inosite. 

ACETONTJRIA. 

This  condition  signifies,  in  general,  albuminous  decompo- 
sition, as  in  advanced  diabetes  mellitus,  infectious  fevers,  ad- 
vanced tuberculosis,  inanition,  carcinoma,  death  of  fetus  in 
utero,  excess  of  animal  diet,  certain  psychoses,  strangulated  her- 
nia, and  eclamptic  seizures  in  infants. 

Legal's  Test. — Treat  Y4  test-tube  of  urine  with  a  few  drops  of  fresh 
concentrated  solution  of  sodium  nitroprussid,  add  a  few  drops  of  acetic 
acid  (to  prevent  reaction  with  creatinin),  and  render  mixture  alkaline 
with  NH4OH.  An  affirmative  reaction  is  shown  by  the  gradual  develop- 
ment of  a  red  color,  deepening  to  purple-red. 

Lieben's  Test. — Distil  500  c.c.  of  the  urine  after  adding  0.5  c.c.  of 
H3P04  (to  prevent  evolution  of  gases),  and  use  the  first  10  c.c.  of  dis- 
tillate. To  this  add  a  few  drops  of  a  dilute  solution  of  iodopotassic 
iodid  and  NaHO.  In  the  presence  of  even  a  trace  of  acetone  crystals 
of  iodoform  are  pptd.  and  are  easily  recognized  by  the  odor. 

DIACETURIA. 

Diacetic  acid,  C6H1003,  is  a  colorless  liquid,  turned  red  by 
ferric  solutions.  It  is  always  of  abnormal  significance,  particu- 
larly in  diabetes  mellitus,  where  its  presence  forewarns  of  coma. 
This  compound  is  also  observed  at  times  in  fevers,  especially  in 
children;  appendicitis,  pneumonia,  pleurisy,  pericarditis,  scurvy, 
and  diseases  of  the  brain.  Diaceturia  also  occurs  as  an  idio- 
pathic  and  very  fatal  autointoxication,  manifested  clinically  by 
vomiting,  dyspnea,  jactitation,  and  coma. 

Von  Jaksch's  Test. — Add  to  the  urine  slowly  a  rather  concentrated 
solution  of  Fe2Cl6,  filter  off  the  phosphatic  ppt.  and  add  more  of  the 
iron  solution.  If  a  claret-red  color  appears,  boil  a  fresh  portion  of  the 
urine  and  treat  another  portion  with  a  little  H,SO4  and  extract  with 
ether.  If  the  iron  solution  gives  no  reaction  with  the  boiled  urine,  but 
gives  a  claret-red  hue  with  the  ethereal  extract,  diacetic  acid  is  prob- 
ably present,  especially  if  the  urine  is  rich  in  acetone.  The  object  in 
boiling  and  treating  with  ether  is  to  exclude  antipyrin,  quinin,  thallin, 
sulphocyanates,  and  salicylic,  carbolic,  acetic,  formic,  and  beta-oxy- 
butyric  acids. 

OXYBUTYRIA. 

Beta-oxybutyric  acid,  C4H803,  is  an  odorless  syrup  readily 
miscible  with  water,  alcohol,  and  ether.  It  is  an  optically  active 
substance,  and,  if  urine  is  dextrorotatory  after  fermentation 
with  yeast,  it  is  very  probable  that  this  compound  is  present. 

Oxybutyria  is  noted  in  severe  cases  of  diabetes  mellitus, 
often  presaging  coma;  also  occasionally  in  infectious  fevers. 


URINE.  455 

ALKAPTONTJRIA. 

Alkapton  is  a  yellow,  resinous,  nitrogenous  substance 
thought  to  be  derived  from  the  putrefaction  of  tyrosin.  Alkap- 
tonuria  is  observed  in  obscure  derangements  of  metabolism, 
especially  in  children  and  phthisic  patients.  Owing  to  the  pres- 
ence of  pyrocatechin,  uroleucic  acid,  and  other  reducing  sub- 
stances, the  urine  darkens  on  standing  (more  quickly  on  adding 
Fe2Cl6),  emits  an  aromatic  odor,  and  reduces  copper  solutions. 

GLYCTJRONIC  ACID. 

This  compound,  C6H1007,  appears  normally  in  the  urine 
in  very  small  amounts  combined  with  K2S04.  In  appreciable 
quantity  it  is  very  likely  to  be  mistaken  for  sugar.  It  is  a 
syrupy  liquid  insoluble  in  ether;  dextrorotatory  itself,  but  in 
combination  levorotatory.  It  gives  a  crystalline  compound  with 
phenyl-hydrazin. 

Glycuronic  acid  appears  in  the  urine  in  a  combined  state 
after  the  administration  of  any  of  the  following  drugs:  Chloral 
(with  urochloralic  acid,  CC13CH2OH),  camphor  (camphoglycu- 
ronic  acid),  naphthalene,  turpentine,  chloroform,  morphin,  curare 
and  arsenic,  copaiba,  acetanilid,  salol,  salicylic  acid,  sulphonal, 
and  nitrobenzol.  If  the  urine  is  dextrorotatory  and  reduces 
copper  solutions,  but  does  not  ferment  with  yeast,  this  acid  is 
probably  present. 

MELANURIA. 

In  this  condition  the  urine  becomes  dark  or  even  black  on 
standing  or  on  heating  with  nitric  acid  or  ferric  chlorid.  It  is 
specially  significant  of  melanotic  sarcoma  in  any  part  of  the 
body,  but  the  pigment  may  not  begin  to  appear  in  the  urine  till 
the  growth  is  far  advanced.  Melanin  is  also  sometimes  found 
in  the  urine  in  cancer  of  the  stomach,  marasmus,  inflammations, 
and  severe  chronic  malaria  (microscopic  pigment-particles). 

Zeller's  Test. — Br  water  causes  a  yellow  ppt.  that  gradually 
blackens. 

CHOLTTBJA. 

Unchanged  bile-piginents  in  the  urine  cause  it  to  have  a 
dark  greenish-yellow  color,  with  a  yellow  foam  on  shaking. 
They  are  present  in  all  diseases  accompanied  by  jaundice  (often 
before  the  appearance  of  the  yellow  hue  in  the  skin),  whether 
from  obstruction  of  the  bile-ducts;  disease  of  the  liver;  or 
decomposition  of  the  blood,  as  in  pernicious  anemia,  malaria, 
or  typhoid  fever,  or  after  internal  hemorrhages.  Poisoning  by 
P  or  arsin  is  manifested  by  choluria. 


456  CLINIC  CHEMISTRY. 

Rasmussen's  Test. — Shake  well  together  1  c.c.  each  of  urine  and 
ordinary  ether  with  6  m.  of  tincture  of  iodin.  On  standing  the  ether 
and  I  separate  as  an  upper  layer,  while  the  stratum  of  urine  below  is 
colored  a  brilliant  green  if  biliverdin  is  present. 

Gmelin's  Test. — Place  a  drop  of  urine  on  a  white  porcelain  plate, 
and  allow  a  drop  of  nitrous  or  fuming  nitric  acid  to  touch  and  mingle 
with  the  other  drop.  In  the  presence  of  bile  a  play  of  colors  will  soon 
appear  in  the  order  of  green,  blue,  violet,  red,  and  yellowish.  The  green 
color  is  indispensable  to  prove  the  presence  of  bile-pigment. 

Stercobilinuria  has  been  observed  in  hepatic  cirrhosis, 
chronic  malaria,  scurvy,  pernicious  anemia,  hemophilia,  and 
after  internal  hemorrhages;  also  in  febrile  and  infectious  dis- 
eases, particularly  pneumonia. 

CYSTINTJRIA. 

Cystein,  NH2CH3SHCCOOH,  is  a  product  of  proteid  me- 
tabolism, never  normally  found  directly  in  the  urine  or  in  the 
body.  It  is  converted  by  atmospheric  0  into  cystin,  2CH3- 
CSKE2COOH:  a  rare  urinary  sediment. 

Cystinuria  is  a  family  disease,  seen  usually  in  children  and 
young  male  adults.  It  has  been  noted  in  connection  with  he- 
patic disorders,  renal  degeneration,  chlorosis,  struma,  intestinal 
putrefaction,  and  acute  articular  rheumatism.  It  is  always 
accompanied  by  diaminuria  originating  in  putrefactive  processes 
due  to  specific  bacteria  in  the  intestines. 

CHYLTIRIA. 

Chyle  in  the  urine  is  a  tropic  condition,  for  the  most 
part,  and  due  to  the  nightly  migrations  of  the  filaria  sanguinis 
hominis.  The  urine  in  filariasis  contains  also  albumin  (coag- 
ulates spontaneously)  and  often  blood,  which  gives  a  pink  color; 
the  parasite  may  be  found  in  the  night  urine.  Earely  chyluria 
is  brought  about  by  great  abdominal  compression  or  by  trauma 
or  disease  setting  up  fistulas  between  the  lymph-canals  and  the 
urinary  channels.  The  milky  appearance  is  cleared  by  shaking 
with  ether. 

LIPURIA. 

Fat-drops,  sometimes  forming  an  oily  upper  coating  on  the 
urine,  are  occasionally  encountered  in  chronic  parenchymatous 
nephritis,  phosphorus  poisoning,  fatty  degeneration  of  the  kid- 
neys, diabetes  mellitus,  calculous  pancreatic  disease,  acute  yel- 
low atrophy,  pregnancy  (normally),  after  fractures  of  the  long 
bones,  opening  of  an  abscess  into  the  urinary  tract  and  follow- 
ing the  administration  of  large  amounts  of  fixed  oils  (rarely 
form  pseudocalculi);  also  rarely  in  heart  disease,  hydronephro- 


URINE.  457 

sis,  gangrene  and  pyemia  of  joints.  The  fat  is  readily  detected 
by  the  microscope  and  by  its  solubility  in  ether.  The  fat  in 
chyluria  is  better  emulsified,  appearing  as  mere  specks. 

LIPACIDURIA. 

Lactic  acid  is  occasionally  present  in  the  urine  in  cases  of 
hepatic  cirrhosis,  acute  yellow  atrophy,  diabetes,  leukemia, 
osteomalacia,  rachitis,  phosphorus  poisoning,  and  trichiniasis. 

HEMATURIA. 

One  part  of  blood  in  1500  makes  the  urine  smoky;  1  to 
500,  bright  red  (chocolate-brown  if  much  acted  on  by  the  urine). 
Blood  in  the  urine  is  best  determined  by  the  use  of  the  micro- 
scope. A  good  chemic  test  for  blood  coloring  matter  is  to  add 
to  a  few  c.c.  of  tincture  of  guaiac  in  a  test-tube  a  few  drops  of 
ozonized  ether,  then  underlay  the  mixture  with  urine.  If  hemo- 
globin is  present  a  blue  ring  will  soon  appear  at  the  line  of 
junction  of  the  two  fluids.  This  ring  does  not  disappear  on 
boiling,  as  does  a  similar  zone  due  to  pus. 

When  the  blood  is  from  the  kidney  the  urine  appears 
smoky;  the  blood  is  usually  slight  in  quantity,  acid,  and  well 
mixed;  and  blood-casts  are  to  be  found.  From  the  renal  pelvis 
the  blood  is  generally  profuse  and  well  mixed  with  the  urine; 
this  hemorrhage  is  generally  unilateral,  as  shown  by  cystoscopy 
or  ureteral  catheterization,  and  tailed  columnar  epithelia  pre- 
vail. Hemorrhage  from  a  ureter  is  manifested  by  long  clots, 
like  earthworms  in  size  and  shape.  There  is  renal  colic  in  the 
passing,  just  as  in  some  cases  of  tubal  or  pelvic  hemorrhage, 
and  hematuria  may  alternate  with  normal  urine  when  the  pas- 
sage is  stopped.  Blood  from  the  bladder  appears  in  large, 
irregular,  bright-red  clots  (sometimes  dark  brown  if  urine  is 
quite  alkaline)  at  the  end  of  micturition.  If  the  bladder  is 
washed  out  with  borax  solution  until  what  comes  away  is  clear, 
and  the  solution  is  again  injected  at  once,  it  will  come  away 
bloody.  Cystoscopy  gives  definite  information  as  to  the  cause 
of  the  bleeding.  Blood  from  the  prostate  appears  toward  or  at 
the  end  of  micturition,  which  is  usually  difficult.  Bright  blood 
from  the  anterior  urethra  is  passed  at  the  beginning  of  micturi- 
tion and  during  the  intervals,  or  can  be  stripped  out.  From  the 
posterior  urethra  it  is  usually  slight  in  quantity  and  comes  at 
the  beginning  or  end  of  micturition  or  both,  sometimes  clotting. 
Pink  semen  indicates  a  hemorrhage  from  the  seminal  vesicles. 
Blood  from  the  vulva,  vagina,  or  uterus  is  readily  distinguished 
by  the  fact  of  menstruation,  by  inspection,  by  washing,  and  if 
necessary  by  catheterization. 


458  CLINIC  CHEMISTRY. 

The  following  are  the  more  common  causes  of  hematuria: 
Trauma,  acute  nephritis,  acute  exacerbations  of  chronic  nephri- 
tis, active  congestion,  filariasis,  embolism,  thrombosis,  urinary 
tuberculosis,  malignant  growths  (profuse  and  apparently  cause- 
less), calculi  (hemorrhage  usually  follows  exertion;  pain  on 
micturition  or  renal  colic),  renal  cysts,  floating  kidney,  blood 
diseases,  irritant  drugs  (turpentine,  cantharis),  neuropathic 
angioneurosis,  acute  infections,  vicarious  menstruation,  strong 
mental  emotions,  uric  acid  infarcts,  severe  inflammations  or 
ulceration,  benign  vesic  growths  (papilloma,  myoma,  fibroma, 
myxoma — bleeding  profuse),  varicose  veins  at  neck  of  bladder, 
sudden  emptying  of  dilated  bladder,  and  the  distoma  hasma- 
tobium. 

HEMOGLOBINTIRIA. 

The  presence  of  blood  coloring  matter  without  the  corpus- 
cles shows  extensive  destruction  of  red  blood-corpuscles,  as  in 
acute  infections,  severe  burns,  transfusion  of  blood,  absorption 
of  hemorrhagic  effusions,  Winckel's  disease,  and  poisoning  by 
KC103,  quinin,  I,  coal-tar  derivatives,  glycerin,  mushrooms; 
carbolic,  hydrochloric,  sulphuric,  and  pyrogallic  acids;  phos- 
phorus; and  H3P,  H3As,  H2S,  and  CO.  Hemoglobinuria  is  also 
seen  in  hepatic  insufficiency  and  following  exposure  to  cold  or 
violent  physic  exertion.  So-called  idiopathic  hemoglobinuria  is 
met  with  at  times  in  malaria,  and  is  accompanied  by  chills, 
fever,  lumbar  pains,  vomiting,  and  diarrhea.  The  urine  is 
porter-colored  and  albuminous.  The  paroxysms  occur  at  inter- 
vals of  weeks  or  months  and  last  a  few  hours. 


PYTJRIA. 

Purulent  urine  is  cloudy  and  deposits  a  creamy  layer.  Pus 
from  the  kidney  tubules  is  usually  small  in  amount  (unless  from 
abscess)  and  is  attended  by  casts  and  acid  urine.  A  larger 
amount  is  met  with  when  the  renal  pelvis  is  involved;  the  urine 
is  usually  acid  and  the  pus  settles  quickly;  micturition  may 
be  frequent,  but  not  painful.  In  vesic  pyuria  the  amount  of 
pus  is  usually  considerable;  the  urine  quickly  loses  its  acidity 
or  is  already  fetid,  ammoniacal,  and  viscid;  and  the  pus  settles 
slowly  and  partially;  micturition  is  usually  both  frequent  and 
painful.  The  sudden  appearance  of  a  large  quantity  of  pus  is 
indicative  of  an  abscess  rupturing  into  the  urinary  channels. 
In  gonorrhea  one  can  tell  whether  the  inflammation  has  ex- 
tended to  the  posterior  urethra  by  having  the  patient  pass 
water  into  two  glass  vessels.  If  the  first  portion  only  of  the 
urine  contains  pus-threads  (tripper  faden)  infection  is  restricted 


URINE.  4.59 

to  the  portion  of  the  canal  in  front  of  the  "cut-off"  muscle,  and 
vice  versa.  Epididymitis  with  suppuration  is  manifested  by 
yellowish  or  greenish-yellow  semen. 

Pus  from  the  kidney  may  be  due  to  tuberculosis,  bacterial 
invasion,  trauma,  new  growth,  calculus,  pyemic  abscess,  or  ex- 
tension of  gonorrhea;  prostatic  obstruction  predisposes  to  up- 
ward extension  of  any  infection.  Pus  from  the  ureter  usually 
means  the  passage  of  a  calculus  or  the  resulting  inflammation. 
Pus  from  the  bladder  may  be  due  to  prostatic  obstruction,  gon- 
orrheal  stricture,  tubercle,  calculus,  trauma,  or  new  growth. 
Pus  from  the  prostate  depends  upon  prostatic  hypertrophy,  gon- 
orrhea, tubercle,  trauma,  stone,  or  tumor.  Pus  from  the  urethra 
may  be  due  to  simple  or  gonorrheal  urethritis,  trauma,  tubercle, 
chancroid,  syphilitic  ulceration,  or  malignant  disease.  Pus 
milked  from  the  seminal  vesicles  is  usually  of  gonorrheal  origin, 
but  may  depend  on  sexual  excesses,  tubercle,  or  new  growth. 
Donne's  reaction  is  the  gelatinization  that  takes  place  on  adding 
some  solid  KHO  to  a  sediment  of  pus. 

PTOMAINS. 

Griffiths  has  isolated  special  alkaloids  from  the  urine  in 
the  following  diseases:  Parotitis,  scarlatina,  diphtheria,  mea- 
sles, pertussis,  glanders,  pneumonia,  epilepsy,  erysipelas,  puer- 
peral fever,  eczema,  influenza^  carcinoma  of  the  uterus,  pleu- 
ritis,  and  angina  pectoris.  Albu  has  also  found  toxins  in  the 
urine  of  patients  with  hectic  phthisis,  exophthalmic  goiter, 
tetanus,  pernicious  anemia,  diabetic  coma,  and  urticaria  due  to 
autointoxication. 


MICROCHEMISTRY  OF  THE  URINE. 

The  presence  of  an  unorganized  sediment  in  urine  signifies, 
as  a  rule,  merely  a  change  in  temperature  or  chemic  reaction, 
owing  to  which  the  solvent  power  of  the  fluid  for  the  substance 
pptd.  is  diminished  or  nullified.  The  presence  of  such  a  sedi- 
ment bears  no  relation  whatever  to  the  amount  of  ingredients 
in  the  urine.  With  the  exception  of  the  slight  cloud  of  mucus 
seen  normally  in  cooled  urine,  organized  urinary  deposits  are 
always  pathologic.  On  the  whole,  however,  cloudy  urine  is  a 
less  serious  indication  than  is  a  very  clear  renal  excretion,  such 
as  we  see  in  diabetes  mellitus  and  chronic  Bright's  disease. 

For  the  accurate  study  of  urinary  sediments  the  micro- 
scope is  absolutely  essential.  A  centrifugal  machine  for  the 
rapid  settling  of  casts  and  other  suspended  matters  must  be 
considered  a  necessary  adjunct  to  the  microscope.  With  the 


460 


CLINIC  CHEMISTRY. 


aid  of  the  centrifuge  one  gains  not  only  more  delicate,  but  more 
correct,  results,  since  the  urine  can  thus  be  examined  in  a  per- 
fectly fresh  condition  before  any  chemic  decomposition  takes 
place  with  precipitation  of  uric  acid,  calcium  oxalate,  earthy  or 
triple  phosphates,  and  other  secondary  sediments  resulting 
from  acid  or  alkaline  fermentation. 

CRYSTALS. 

The  only  colored  urinary  crystals  are  uric  acid,  ammonium 
urate,  and  rarely  cystin  and  acid  urates,  hematoidin,  leucin, 


Fig.  57.— Sodium  Urate  Crystals. 

and  tyrosin.  All  these  crystals  owe  their  color  to  urochrom, 
and  are  darker  or  lighter,  according  to  the  amount  of  this  pig- 
ment. 

Uric  acid  (Fig.  1,  Plate  VII)  is  pptd.  from  its  normal  occur- 
rence as  urates  by  an  increase  of  acidity,  particularly  when  the 
urine  is  of  low  sp.  gr.  and  deficient  in  pigment.  To  the  naked 
eye  uric  acid  appears  as  a  crystalline  sediment  resembling  grains 
of  red  sand  or  Cayenne  pepper.  Under  the  microscope  it  appears 
as  large  and  beautiful  crystals  of  various  forms,  the  lozenge  shape 
predominating,  frequently  arranged  in  a  superimposed  manner 
into  rosettes  and  other  composite  combinations.  Uric  acid 


PLATE    VII. 


>'///.  / 


xf"  V        -  v^> 


,/. 

/.& 


^f 

V- 


Fig.  3 


/y^.x? 


URINARY  CRYSTALS. 


URINE. 


461 


crystals  are  readily  distinguished  from  any  other  (except  urates 
and  cystin)  by  their  lemon-yellow  or  red-brown  color. 

Uric  acid  deposits  are  frequently  due  to  excess  of  meat 
in  sedentary  livers  and  in  the  excessive  catabolism  ("uric  acid 
diathesis")  of  deficient  oxidation.  They  are  also  observed  in 
fevers,  after  gouty  paroxysms,  in  the  early  stage  of  chronic  in- 
terstitial nephritis,  and  during  recovery  from  aeute  exanthems 
or  acute  nephritis. 

Acid  urates  are  usually  amorphous,  but  rarely  appear  as 
fan-shaped  and  circular  radiating  crystals  of  a  reddish-brown 


Fig.  58.— Cptin  Crystals. 

or  yellowish  tint.  Uric  acid  and  urates  are  readily  soluble  in 
alkaline  hydrates. 

Ammonium  urate  (Fig.  3,  Plate  VII)  appears  in  the  urine 
after  it  has  undergone  alkaline  fermentation;  it  usually  takes 
the  form  of  little  brown  balls  with  spicules — the  so-called  "thorn- 
apple,"  "hedge-hog"  crystals;  sometimes  a  "sheaf  of  wheat" 
clump  of  fine  needles  with  a  central  spherule. 

Cystin  is  rarely  met  with  as  a  lemon-colored  deposit  in 
faintly  acid  urine.  It  contains  26  per  cent,  of  S,  and  on  stand- 
ing for  some  time  is  apt  to  turn  of  a  greenish  hue  and  develop 
the  odor  of  H2S.  The  microscope  reveals  highly  refractive 


462 


CLINIC  CHEMISTRY. 


"mother-of-pearl"  hexagonal  crystals,  which  are  distinguished 
from  those  of  uric  acid  having  a  similar  appearance  by  treating 
the  specimen  on  the  slide  with  a  drop  of  KE4OH.  The  ammo- 
nia is  allowed  to  evaporate,  with  the  result  that  the  cystin 
crystals  remain  unchanged,  while  uric  acid  crystals  are  changed 
to  ammonium  urate  spherules.  Cystin  is  soluble  in  HC1;  uric 
acid  is  not. 

Leucin  and  tyrosin  (Fig.  2,  Plate  VII)  are  nearly  always 
associated  in  the  urine,  being  observed  chiefly  in  acute  yellow 
atrophy  and  phosphorus  poisoning.  The  former  appears  in  the 


Fig.  59. — Calcium  Oxalate  Crystals. 

shape  of  somewhat  striated  yellowish  spheres  resembling  oil- 
drops,  from  which  they  are  differentiated  by  their  insolubility 
in  ether.  Tyrosin  is  observed  in  the  form  of  tufts  or  sheaves 
of  very  fine  needles,  snow-white  when  viewed  en  masse. 

Hematoidin  (bilirubin)  crystals  are  often  deposited  in  urine 
containing  bile  and  following  hemorrhages.  They  appear  as 
yellow  or  ruby-red  needle  clusters  or  rhombic  plates,  which 
show  a  green  rim  on  adding  a  drop  of  HN03. 

The  colorless  crystals  of  the  urine  include  triple  phos- 
phates, calcium  oxalate,  calcium  phosphate,  calcium  sulphate, 
cholesterin,  calcium  carbonate,  and  fatty  acid  crystals. 


URINE. 


463 


The  so-called  "triple"  phosphate  (Fig.  5,  Plate  VII)  of  am- 
monium and  magnesium,  NH4MgP04,  is  seen  normally  in  urine 
which  has  undergone  ammoniacal  fermentation  after  voiding. 
When  present  in  freshly  passed  urine  such  a  deposit  is  always 
pathologic,  indicating  ammoniacal  decomposition  within  the 
bladder  as  both  a  cause  and  a  result  of  cystitis.  Triple  phosphate 
crystals  are  relatively  large  and  colorless,  having  the  form  ordi- 
narily of  a  triangular  prism  with  beveled  ends;  hence  the  name 
"coffin-lid"  crystals.  Collections  of  these  crystals  often  form  a 
glistening  film  on  the  surface  of  stale  urine  and  the  sides  of  the 


Fig.  60.— Hippuric  Acid  Crystals. 

container;  this  appearance,  under  the  designation  of  "kiestein," 
was  formerly  believed  to  be  a  sign  of  pregnancy. 

CaH(P04)  crystals  are  sometimes  observed  in  feebly  acid 
urine  as  wedge-shaped  or  conic  scaly  forms,  usually  grouped  in 
a  radiating  manner  point  to  point.  They  are  distinguished,  like 
phosphates  generally,  by  their  ready  solubility  in  acetic  acid. 
A  deposit  of  this  nature  is  rarely  met  with  in  health  when  the 
urine  is  rich  in  lime-salts,  as  after  a  full  meal  of  certain  vege- 
tables. Pathologically  the  deposit  has  been  noted  in  phthisis, 
pyloric  cancer,  calculi,  and  obstinate  chronic  rheumatism. 

Calcium  oxalate  (Fig.  4,  Plate  VII)  is  rather  a  common  sedi- 


464  CLINIC  CHEMISTRY. 

inent,  often  mistaken  macroscopically  for  a  cloud  of  mucus,  with 
which,  for  obvious  reasons,  it  is  often  co-existent.  It  is  found 
both  in  acid  and  in  alkaline  urine.  CaC204  crystals  are  usually 
octahedral  in  shape,  giving  the  appearance  of  a  square  crossed  by 
two  diagonal  bright  lines,  like  the  back  of  a  square  envelope. 
They  are  much  smaller  than  those  of  the  triple  phosphate,  from 
which  they  are  further  distinguished  by  their  insolubility  in 
acetic  acid.  Much  rarer  forms  of  calcium  oxalate  crystals  are 
those  resembling  a  dumb-bell,  and  the  oval  and  circular  crystals 
with  bright  centers  showing  biconcavity. 

Hippuric  acid  is  occasionally  met  with  as  a  slight  urinary 
sediment,  in  the  form  microscopically  of  fine  needles  or  of  four- 
sided  rhombic  prisms  with  beveled  ends  and  edges.  It  is  sol- 
uble in  alcohol;  insoluble  in  acetic  acid. 

Cholesterin — in  large,  thin,  and  nearly  transparent  plates 
with  broken  corners — is  occasionally  encountered  in  the  urine 
of  cystitis,  diabetes,  chyluria,  tabes,  pregnancy,  jaundice,  ne- 
phritis, fatty  degeneration  of  the  kidneys,  and  after  evacuation 
of  an  abscess  into  the  urinary  tract  or  the  long-continued  ad- 
ministration of  bromids.  Treated  with  dilute  H^SC^  and  then 
with  I  solution,  these  crystals  turn  violet,  turquoise,  then  blue. 

Calcium  sulphate  is  a  very  rare  sediment,  occurring  only 
in  acid  urine  of  high  sp.  gr.  The  crystals  are  radiating,  color- 
less needles.  Calcium  carbonate  is  also  an  exceedingly  rare 
deposit  in  the  human  renal  secretion.  It  is  found  only  in  alka- 
line urine  as  a  whitish  deposit  that  dissolves  with  effervescence 
in  dilute  acids,  and  which  under  the  microscope  is  shown  to  be 
composed  of  concretions  of  little  spheroids. 

Fatty  acid  crystals  are  sometimes  seen  with  the  microscope 
as  fine,  bright  needles  adhering  to  fat-drops  and  fatty  cells. 

GRANULES. 

Acid  urates  of  K  and  Na  are,  by  far,  the  most  common 
urinary  deposits,  forming  sediments  that  are  usually  amorphous 
and  vary  in  color  from  a  light  pink  to  a  deep  red — rarely  color- 
less. Under  the  microscope  they  appear  as  pink,  granular, 
moss-like  beds,  which  clear  up  on  warming  or  on  treating  with 
a  drop  of  NH4OH.  Calcium  urate  is  of  rare  occurrence  as  a 
urinary  sediment,  appearing  as  a  light-gray,  amorphous  powder. 
Like  the  other  urates,  it  is  found  only  in  urine  of  acid  reaction; 
these  mixed  urates  constitute  the  well-known  "brick-dust"  de- 
posit of  cold  and  dense  urines.  The  white  urates  of  young 
infants  consist  chiefly  of  amorphous  ammonium  urate.  Urine 
rich  in  urates  after  being  in  a  bottle  for  some  time  leaves  a 
very  adherent  film  of  these  on  the  inside  of  the  flask. 


URINE.  465 

The  earthy  phosphates  (Ca  and  Mg)  constitute  the  most 
common  sediment  of  alkaline  urines.  They  are  easily  soluble 
in  acetic  acid,  being  in  this  way  discriminated  from  other  uri- 
nary deposits.  The  color  of  a  phosphatic  sediment  is  usually 
gray,  but  in  the  presence  of  hemoglobin  has  a  reddish  tinge, 
and"  sympexia  from  the  prostate  are  often  colored  blue  or  yel- 
lowish. Cloudy  urine  from  these  granular  phosphates  is  very 
often  seen  after  a  full  meal  of  vegetables,  but  the  constant 
presence  of  phosphaturia  indicates,  as  a  rule,  a  low  general 
metabolism. 

The  black  pigment  melanin  occurs  in  lumpy,  microscopic 
granules,  soluble  only  in  boiling  mineral  acids  or  strong  solu- 
tions of  the  caustic  alkalies. 

Irregular  masses,  or  rhomboidal  crystals,  of  indigo  are 
rarely  noticed  in  the  urine,  especially  when  this  has  undergone 
putrefactive  changes  with  oxidation  of  indican.  The  blue  par- 
ticles may  also  be  derived  from  the  underwear. 

CASTS. 

Tube-casts,  or  cylinders,  are  molds  of  the  renal  tubules, 
formed  by  the  transudation  of  coagulable  material,  and  by  exu- 
dation from  and  degeneration  of  the  epithelial  cells  lining  these 
tubes.  The  casts  contract  and  entangle  formed  elements  and 
crystals,  and  are  finally  washed  out  by  the  pressure  of  liquid 
from  the  glomeruli.  They  are  nearly,  if  not  quite,  always  ac- 
companied by  albumin. 

Tube-casts  are  of  prime  importance  in  the  diagnosis  and 
prognosis  of  renal  diseases.  Small  casts  (from  the  narrow  and 
convoluted  tubules)  characterize  acute  and  superficial  lesions, 
as  a  rule,  while  broad  casts  (from  the  straight  collecting  tu- 
bules) are  more  often  observed  in  well-advanced  degenerative 
cases.  Casts  are  distinguished  from  foreign  bodies  by  their 
cylindric,  finger-shaped  form,  often  rounded  at  one  or  both 
ends;  and  by  their  more  regular  contour  and  lesser  opacity. 

The  simplest  type  of  tube-cast  is  the  hyaline,  which  is  so 
nearly  transparent  as  to  require  a  dim  background  for  its  ready 
detection.  A  few  hyaline  casts,  with  a  trifling  amount  of  albu- 
min, are  often  to  be  found  in  transient  renal  circulatory  dis- 
turbances, such  as  may  be  caused  by  a  long  bicycle-ride,  over- 
eating or  overdrinking,  mental  or  physic  strain,  fevers,  lithemia, 
embolism,  and  ether  or  chloroform  anesthesia.  They  are  also 
seen  in  cases  of  cyanotic  kidney,  due  to  passive  congestion,  and 
occasionally  in  anemia,  malnutrition  and  suboxidation,  nephro- 
lithiasis,  pyelitis,  floating  kidney,  and  even  with  tumors  of  the 
bladder.  Jaundice  may  be  accompanied  by  yellow,  hyaline  casts. 


466 


CLINIC  CHEMISTRY. 


Chronic  interstitial  nephritis  is  manifested  by  the  constant  or 
intermittent  occurrence  of  small  numbers  of  hyaline  casts,  and 
still  fewer,  faintly  granular  ones,  along  with  polyuria  and  slight 
albuminuria  and  distinctive  cardiovascular  changes. 

The  band-like  so-called  cylindroids  are  similar  in  appear- 
ance and  nearly  equal  in  significance  to  hyaline  casts,  but  are 
very  much  larger.  Long,  pale,  branching,  striated  mucin  bands 
are  always  present  with  excess  of  mucus,  and  hence  are  noted 
in  any  dense,  acid,  irritating  urine. 

Mixed  casts,  composed  of  a  hyaline  matrix,  beset  with 


Fig.  61.— Narrow  Hyaline  Casts. 

blood-  or  pus-  cells,  epithelia,  nuclei,  or  granules,  characterize 
acute  parenchymatous  or  diffuse  nephritis,  being  found  here 
in  large  numbers;  and  also  the  exacerbations  of  chronic  ne- 
phritis. The  irregular  blood-casts  proper  are  likewise  noted  in 
renal  hemorrhage  from  any  cause,  and  in  small  numbers  from 
infarction  or  marked  congestion  of  the  kidney.  When  retained 
long  in  the  tubules  the  corpuscles  break  down  into  dark,  rusty 
granules,  forming,  thus,  rarely  hemoglobin-casts. 

Fibrinous  casts  are  simply  blood-stained  hyaline  molds,  and 
are  of  common  occurrence  in  hemorrhagic  nephritis.  Irregular 
yellow-brown  pseudocasts  of  wavy  fibrin  may  be  found  in  many 


URINE. 


467 


forms  of  hematuria,  Cast-like  conglomerations  of  pus-cells  are 
significant  of  renal  abscess  or  pyonephrosis,  but  one  should  not 
mistake  for  these  groups  the  larger  clumps  due  to  pyelitis,  pros- 
tatitis,  or  leucorrhea. 

Granular  casts  denote  most  often  subacute  or  chronic 
parenchymatous  nephritis,  especially  when  accompanied  by  con- 
siderable albumin  and  dropsy.  The  coarser  the  granulations, 
the  more  acute  is  the  disease;  the  finer,  the  more  chronic. 
These  finely  granulo-hyaline  casts  are  often  observed  in  the 
same  conditions  as  simple  hyaline  casts:  for  instance,  in  uric- 


Fig.  62.— Epithelial  Casts. 

acidemia.  Coarsely  granular  casts  have  been  observed  in  renal 
cysts.  Brownish,  blood-stained,  granular  casts  are  sometimes 
encountered  in  scurvy,  hemophilia,  and  other  blood  dyscrasias 
and  in  hemorrhagic  nephritis. 

Fatty  casts  are  formed  secondarily  from  granular  and  epi- 
thelial casts,  and  indicate  always  a  chronic  degenerative  process. 
The  fat-globules  imbedded  in  these  casts  are  very  readily  recog- 
nized by  their  glistening,  highly  refractive  appearance.  Fatty 
cylinders  are  most  abundant  in  the  large  white  kidney  of  very 
chronic  nephritis.  Irregular,  cast-like  conglomerations  of  fat- 
drops,  accompanied  at  times  by  fatty  acid  needles,  are  some- 


4C8 


CLINIC  CHEMISTRY. 


Fig,  63. — Granular  Casts. 


Fig.  64.— Waxy  Casts. 


URINE. 


469 


times  met  with  in  renal  abscess,  fracture  of  the  long  bones,  and 
in  poisoning  by  P,  As,  Sb,  and  iodoform. 

Waxy  or  amyloid  casts  appear  as  highly  refractive,  yellow- 
ish, often  cloudy,  wavy,  and  fluted  cylinders.  They  are  quite 
brittle;  hence  often  much  broken  and  irregular.  They  are  at- 
tacked hardly  at  all  by  acetic  acid,  which  is  a  further  distinction 
from  the  hyaline  cylinders.  Some  of  them,  when  retained  for 
a  long  time  in  the  tubules,  give  the  amyloid  reaction:  a  ma- 
hogany color  with  a  dilute  solution  of  iodopotassic  iodid,  turn- 
ing to  a  dirty  violet  on  addition  of  dilute  H2S04.  Waxy  frag- 


Fig.  65.— False  Casts. 

ments  may  be  found  in  subacute  and  chronic  parenchymatous 
nephritis  and  in  renal  amyloidosis,  which  last  is  usually  accom- 
panied by  amyloid  liver  and  spleen. 

Bacterial  casts  in  freshly  passed  urine  are  suggestive  of 
interstitial  suppurative  nephritis  or  an  ascending  pyelonephri- 
tis. Similar  groups  of  micrococci  (zooglea)  deposited  on  mucous 
threads  are  apt  to  occur  in  any  urine  that  has  stood  for  some 
hours,  particularly  in  warm  weather.  Bacterial  casts  resemble 
somewhat  pale,  granular  casts,  and  are  very  resistant  even  to 
strong  chemic  reagents. 

Deposits  of  urates  on  mucin  bands  and  hyaline  cylinders 


470 


CLINIC  CHEMISTRY. 


give  rise  to  yellowish,  pink,  or  red-brown  cast-like  formations 
("catarrhal  casts"),  which  have  at  times  been  mistaken  for 
granular  casts.  These  conglomerations  may  consist  either  of 
amorphous  urates  or  of  calcium  oxalate  or  the  crystalline  urates 
of  sodium  or  ammonium.  They  are  readily  distinguished  from 
granular  casts  by  their  solubility  in  warm  water  or  in  alkalies. 
Uratic  pseudocasts  are  of  frequent  occurrence  in  the  concen- 
trated urine  of  lithemic  persons,  especially  infants  and  children. 
Similar  concretions  may  be  observed  occasionally  in  any  cold, 
dense,  acid  urine,  with  "brick-dust"  deposit  of  acid  urates. 

From  the  above  brief  resume  it  will  be  noted:    (1)  that 
tube-casts  have  general  as  well  as  local  significance;  (2)  that  no 


Fig.  66,— Pus-corpuscles. 

one  type  is  in  itself  pathognomonic  of  a  single  definite  lesion; 
(3)  that  the  various  types  are  pathologically  and  clinically  pro- 
gressive, changing  with  the  stages  of  the  underlying  disease, 
according  to  its  particular  nature. 

CELLS. 

A  few  leucocytes  are  present  in  every  urine.  Any  consid- 
erable number  indicates  irritation,  inflammation,  or  ulceration 
of  some  part  of  the  genito-urinary  tract.  Pus-cells  are  readily 
distinguished  by  their  granular  appearance  and  by  their  nuclei 
(rarely  mononuclear),  which  if  not  apparent  can  be  brought  out 
by  treating  with  a  drop  of  dilute  acetic  acid.  The  nuclei  are 


URINE.  471 

often  coalesced  in  horseshoe  form,  made  evident  by  staining. 
Von  Jaksch  states  that  leucocytes  are  stained  a  deep  mahogany- 
brown  (glycogen  reaction)  by  KI  solution,  while  small  round 
cells  are  stained  light  yellow.  In  the  presence  of  alkalies  pus- 
corpuscles  are  broken  down  into  a  glairy,  mucus-like  mass,  in 
which  only  the  nuclei  may  be  visible.  Albumin  is  always  pres- 
ent in  the  supernatant  liquid  when  there  is  a  macroscopic  de- 
posit of  pus.  In  gonorrheal  urethritis  the  pus-cells  are  held 
together  in  threads  and  bands  by  mucin,  and  are  sometimes 
attended  by  spermatozoa.  The  purulent  urine  of  chronic  cys- 
titis is  generally  ammoniacal,  except  in  tubercular  and  calculous 
cases.  A  sudden  gush  of  greenish  pus  is  likely  to  have  come 
from  a  ruptured  abscess  or  pyonephrosis. 

Mucus  corpuscles  vary  in  size  from  a  pus-cell  to  several 
times  larger.    They  are  pale,  rather  irregular,  finely  granular, 


Fig.  67. — Normal  Blood-corpuscles. 

and  non-nucleated.  They  are  always  accompanied  by  mucin 
bands.  An  excess  of  mucus  is  observed  in  irritative  conditions 
below  the  kidneys.  The  nebecula  in  these  cases  is  greatly  in- 
creased, and  the  urine  becomes  viscid,  slimy,  and  ropy. 

Red  blood-corpuscles,  if  present,  on  centrifugation  are 
thrown  down  in  a  dense,  reddish  layer,  of  a  much  deeper  shade 
usually  than  the  urates.  The  supernatant  liquid  shows  a  trace 
or  more  of  albumin.  Under  the  microscope  the  colored  blood- 
cells  are  ordinarily  easily  recognized  by  their  biconcave  discoid 
form.  The  difference  in  focus  between  the  central  circle  and 
the  outer  ring  is  shown  by  the  separate  focus  of  each,  one  ap- 
pearing dark  when  the  other  is  light.  Normal  blood-corpuscles 
are  yellow  and  are  not  arranged  in  rouleaux  as  in  blood  from 
other  sources.  In  dense  urine  they  become  crenated.  Abnor- 
mal blood-cells,  such  as  have  been  in  the  urine  for  some  time 


472 


CLINIC  CHEMISTRY. 


(blood-  rings  or  shadows,  "washed-out"  blood-corpuscles),  are 
swollen,  biconvex,  and  devoid  of  color  and  about  two-thirds  the 
size  of  normal  cells;  a  few  of  these  are  commonly  to  be  seen 
throughout  the  intervals  of  renal  colic  due  to  stone.  Blood- 
casts  are  certain  evidence  of  a  renal  origin. 

Epithelial  cells  from  the  genito-urinary  tract  differ  in  size 
and  shape  according  to  their  anatomic  source,  the  layer  from 
which  they  were  derived,  and  the  reaction  and  density  of  the 
urine.  A  lining  of  stratified  epithelium — first  layer  flat,  or 
squamous;  middle  layer  cuboidal,  or  round;  deep  layer  co- 
lumnar, or  cylindric — exists  in  the  renal  pelves,  ureters,  blad- 
der, urethra,  vagina,  and  cervix  of  the  uterus;  a  simple  epithe- 
lial lining  obtains  in  'the  uriniferous  tubules,  the  prostate, 
ejaculatory  ducts,  Bartholinian  gland,  and  uterine  mucosa. 

The  size  of  epithelia  from  the  same  site  varies  at  different 


c  ^^    g 

Fig.  68.— Urinary  Epithelia. 

times;  thus,  in  light,  slightly  acid  or  alkaline  urines  the  cells 
swell  up,  while  in  dense,  acid  urines  they  shrink.  The  leuco- 
cytes, which  are  practically  always  to  be  found,  also  shrink  or 
swell  in  the  same  proportion,  and  are  convenient  as  a  standard 
for  the  measurement  of  epithelia  with  a  view  to  determine  the 
origin  of  the  latter.  Epithelia  are  distinguished  from  leuco- 
cytes by  their  larger  size  and  the  presence  of  a  single  nucleus 
usually  distinct  without  the  aid  of  reagents. 

The  round  or  cuboidal  renal  cells  are  about  a  third  larger 
than  the  leucocytes  in  the  same  specimen.  They  are  highly 
granular,  with  a  relatively  large  nucleus.  The  round  cells  from 
the  prostate  and  the  ureters  are  twice  the  size  of  pus-corpuscles. 
The  small,  brown,  caudate  cells  from  the  renal  pelvis  are  a 
little  larger  than  those  from  the  ureters,  and  are  commonly 
arranged  in  groups  like  the  shingles  on  a  roof;  their  tails  are 


URINE.  473 

often  curved  and  sometimes  bifurcated.  These  cells  are  always 
accompanied  by  more  or  less  blood  and  often  by  crystals.  The 
small  round  cells  from  the  deeper  layer  of  the  pelvis  are  often 
arranged  in  clumps  and  are  always  accompanied  by  pus.  Epi- 
thelia  from  the  calices  are  rarely  found.  They  are  somewhat 
larger  than  the  tubule-cells  and  generally  overlap  one  another, 
forming  clumps.  They  have  a  large  prominent  nucleus  and  are 
seen  in  acute  pyelitis. 

Epithelia  from  the  neck  of  the  bladder  are  three  to  five 
times  the  size  of  a  leucocyte.  They  are  usually  round  or  oval, 
with  a  small,  prominent  nucleus.  From  the  fundus  the  cells 
are  still  larger,  and  if  from  the  superficial  layer  are  flat,  thin, 
and  polygonal,  and  joined  by  their  edges;  thin  and  circular 
from  near  the  ureteral  orifices. 

Male  urethral  cells  are  one  and  one-half  to  two  times  as 
large  as  leucocytes,  and  are  very  irregular.  They  are  commonly 
clumped  with  pus  in  threads  of  mucus.  The  round  or  pyriform 
prostatic  cells  may  be  accompanied  by  prostatic  casts,  which  are 
simply  long  shreds  of  mucin  entangling  phosphates.  Seminal 
cells  are  readily  distinguished  by  the  presence  of  spermatozoa 
both  free  and  in  the  cell.  These  cells  are  of  medium  size,  round 
in  form,  and  highly  granular,  with  an  ill-defined  nucleus. 

The  largest  cells  encountered  in  urine  are  those  from  the 
vagina.  They  are  squamous,  warped,  and  arranged  overlapping 
in  sheets,  only  slightly  granular,  contain  many  bacteria,  and 
are  commonly  accompanied  by  pus-cells.  They  are  due  to  leu- 
corrhea,  menstruation,  or  masturbation.  Vulvar  cells  and  cells 
from  the  glans  penis  are  apt  to  take  on  the  character  of  dried, 
jagged,  epidermal  scales  without  a  nucleus  and  often  studded 
with  fat  and  dirt:  the  so-called  smegma. 

Small,  ciliated  epithelia  may  come  from  the  body  of  the 
uterus  (prismatic,  with  ordinary  vaginal  cells  during  menstrua- 
tion) or  the  ejaculatory  ducts.  The  cells  from  the  female  ure- 
thra are  large  and  round  or  oval,  quite  similar  to  those  from 
the  neck  of  the  bladder.  Those  from  the  Bartholinian  glands 
are  exactly  the  counterpart  of  the  prostatic  cells.  Epithelia 
from  the  neck  of  the  uterus  are  flat,  cuboidal,  and  columnar, 
and  quite  irregular;  they  are  somewhat  smaller  than  those  from 
the  vagina.  Decidual  cells  are  large,  round,  polygonal,  or 
spindle-shaped,  with  large  nuclei  and  nucleoli. 

While  a  small  number  of  epithelia  (vesic,  especially)  may 
be  said  to  represent  the  normal  "wear  and  tear'7  of  the  mucous 
membrane,  large  numbers  indicate  irritation  or  inflammation. 

Fatty  degeneration  of  cells,  except  vaginal,  is  an  indication 
of  a  chronic  inflammatory  condition  of  the  part  involved.  If 


474  CLINIC  CHEMISTRY. 

the  fat-drops  have  been  washed  out,  vacuoles  are  left.  Multiple 
nuclei  are  generally  evidence  of  adjacent  inflammation  exert- 
ing pressure,  as  in  the  case  of  a  perirenal  or  perivesic  abscess. 
Fatty  renal  cells  are  noted,  not  only  in  subacute  and  chronic 
diffuse  nephritis,  but  also  in  the  fatty  stage  of  acute  nephritis 
and  severe  renal  congestion.  These  fatty  renal  cells  are  not  to 
be  mistaken  for  the  compound  granule-cells,  which  are  larger, 
round  epithelia  that  have  undergone  complete  fatty  degenera- 
tion, and  show  no  nucleus,  but  sometimes  fatty  needles.  They 
have  been  observed  in  chronic  pyelitis,  cystitis,  prostatitis,  and 
urethritis;  also  in  ulcerations  and  in  the  contents  of  a  ruptured 
abscess  or  cysts,  as  well  as  in  vaginal  secretions. 

Chyle  or  fat  in  the  urine  is  recognized  microscopically  as 
highly  refracting  globules  with  dark,  broad  borders,  dissolving 
on  the  addition  of  ether. 

All  urine  containing  any  appreciable  amount  of  blood  al- 
ways contains  wavy  bands  of  fibrin  with  refractive  margins. 
Connective-tissue  shreds  are  made  up  of  bundles  of  wavy,  highly 
refractive  fibers  and  fibrillae.  They  are  found  in  ulceration, 
suppuration,  hemorrhage,  trauma,  tumors,  prostatic  hyper- 
trophy and  inflammation,  renal  cirrhosis,  renal  atrophy,  and 
all  intense  inflammatory  processes. 

Spermatozoa  are  found  in  the  urine  after  sexual  intercourse 
or  emissions  and  almost  constantly  in  the  very  rare  condition 
of  true  spermatorrhea.  Spermatozoa  are  about  one  six-hun- 
dredth of  an  inch  long  and  consist  of  a  flattened,  oval  head  and 
a  long,  tapering  tail.  The  motion  of  these  bodies  soon  ceases 
in  the  urine.  In  spermatocystitis  the  head  often  becomes  gran- 
ular, like  a  pus-corpuscle. 

Amyloid  corpuscles  from  the  prostate  are  pale,  irregular, 
oval,  or  angular  concentric  bodies  having  a  high  refraction  and 
often  a  central  nucleus.  They  are  colloid  in  structure,  and  are 
increased  in  numbers  in  prostatic  hypertrophy.  They  may  form 
the  basis  of  prostatic  concretions. 

Fragments  of  urinary  tumors  are  occasionally  found,  par- 
ticularly papillomatous  shreds  and  sarcoma-corpuscles.  These 
are  compact,  granular  bodies  a  trifle  smaller  than  pus-cells,  and 
are  nearly  always  accompanied  by  large  shreds  of  connective 
tissue.  Cancer-cells  and  the  pigmented  cells  of  melanoma  are 
rarely  seen. 

The  most  common  parasite  found  in  the  urine  is  the  tri- 
chomonas  vaginalis:  a  harmless  habitant  of  the  vagina  in  cases 
of  leucorrhea.  In  the  bladder  it  may  give  rise  to  dysuria  and 
hematuria.  It  has  an  oval  head,  often  nucleated,  with  a  large 
tail  or  several  flagella.  It  is  much  larger  than  spermatozoa. 


URINE.  475 

BACTERIA. 

The  flora  of  the  urethra,  according  to  Warren,  includes  the 
bacterium  coli  commune,  coccobacillus  liquefaciens  urethras, 
bacillus  urethras  non-liquefaciens,  leptothrix  urethras,  diplo- 
coccus  candidus  urethras,  pseudogonococcus,  gonococcus  of 
Neisser,  staphylococcus  ureas  liquefaciens,  streptococcus  py- 
ogenes,  streptococcus  liquefaciens  urethras,  sarcina  urethras, 
smegma  bacillus,  tubercle  bacillus,  bacillus  typhosus,  staphylo- 
cocci  pyogenes  aureus  and  albus,  and  streptobacillus  anthra- 
coides. 

Of  the  vesic  flora,  the  bacterium  coli  commune  is  the  most 
common  cause  of  acid  cystitis,  gaining  access  to  the  urine  in 
case  of  obstinate  constipation  or  other  bowel  trouble.  The 
urobacillus  liquefaciens  septicus  (proteus  Hauser)  is  pyogenic 
and  decomposes  urea,  setting  up  ammoniacal  cystitis  and  pye- 
lonephritis. The  diplococcus  and  the  staphylococcus  ureas 


Fig.  69.— Micrococcus  Urese. 

liquefaciens  (Melchior)  also  rapidly  decompose  urea;  the  strep- 
tobacillus anthracoides  slowly.  The  staphylococci  aureus  and 
albus  are  common  pus-producers  and  also  decompose  urea.  The 
bacillus  lactis  aerogenes  is  responsible  for  most  cases  of  pneu- 
maturia,  in  which  bubbles  of  gas  are  passed  with  the  urine. 

In  urine  that  is  undergoing  putrefactive  changes  micro- 
cocci  ureas  are  most  constant.  These  appear  under  the  micro- 
scope as  trembling  points,  isolated  or  collected  in  strings.  The 
bacterium  termo,  another  common  putrefactive  micro-organism, 
appears  as  comparatively  large,  oblong  cells,  often  joined  in 
pairs  or  longer  chains.  In  stale  urine  we  often  see  zooglea 
groups  of  cocci:  that  is,  masses  of  cocci  enveloped  in  a  color- 
less, gelatinous  capsule.  The  bacillus  subtilis,  or  hay  bacillus, 
is  a  large  bacillus  frequently  found  in  decomposed  urine,  and 
various  actively  motile  vibriones  are  likely  to  gain  access  from 
the  air  or  from  unclean  vessels.  Leptothrix  threads  are  some- 


476  CLINIC  CHEMISTRY. 

times  seen  and  in  large  numbers  may  give  rise  to  mycotic  cys- 
titis; in  such  cases  they  may  be  seen  in  the  urine  as  whitish 
pellicles  with  the  naked  eye.  Yeast-cells,  or  saccharomyceta?, 
are  found  in  acid  urine,  particularly  in  cases  of  diabetes  mel- 
litus.  They  are  distinguished  from  colorless  blood-cells  by 
their  oval  shape,  irregular  size,  budding,  and  nuclei.  Oidium 
lactis  is  a  common  mold-fungus  of  the  acid  urine,  and  consists 
of  jointed  stems  (mycelia)  and  vacuolated  spores  (conidia).  The 
penicillium  glaucum  and  aspergilli  are  much  less  frequent  in 
urine.  The  hypha  of  the  latter  fungi  ends  in  a  spheric  or  club- 
shaped  vesicle;  the  hyphae  of  the  former  divide  and  subdivide 
into  thread-like  basidia  and  streigmata. 

Of  pathogenic  urinary  bacteria  the  tubercle  bacillus  is  most 
important.  It  is  pyogenic  and  gives  rise  to  acid  cystitis  and 
pyelitis.  Tubercular  lesions  may  be  either  primary  or  second- 
ary. The  smegma  bacillus  resembles  the  tubercle  bacillus  in 
form  and  in  reaction  to  the  common  stains;  it  is  usually  ex- 
cluded by  treating  with  alcohol,  which  decolorizes  the  smegma, 
but  not  the  tubercle  bacillus.  To  detect  tubercle  bacilli  in  the 
urine  centrifugate,  wash  sediment  by  decantation  with  dis- 
tilled water,  and  centrifugate  again;  fix  sediment  by  heating 
gently  over  a  copper  or  iron  plate;  stain  with  carbol-fuchsin, 
then  decolorize  in  20-per-cent.  HN03  and  again  in  70-per-cent. 
alcohol  (for  at  least  ten  minutes),  and  counterstain  with 
aqueous  solution  of  methylene  blue.  Tubercle  bacilli  are  often 
difficult  to  find  when  present  in  urine,  and  in  case  of  doubt  some 
of  the  urine  and  sediment  should  be  injected  into  guinea-pigs. 

The  gonococcus  is  a  frequent  habitant  of  the  genito- 
urinary tract,  and  is  the  commonest  cause  of  suppuration  in 
both  sexes.  Gonorrhea,  is  usually  a  mixed  infection.  Coplin's 
method  of  staining  gonococci  is  as  follows:  Stain  with  saturated 
alcoholic  solution  of  methylene  blue  for  five  to  fifteen  minutes, 
wash  with  water,  and  then  stain  with  saturated  alcoholic  solu- 
tion of  eosin  for  the  same  length  of  time.  Wash  in  water,  dry, 
and  mount.  The  nucleus  of  the  pus-corpuscle  as  well  as  the 
diplococci  contained  in  the  cells  are  stained  blue;  the  proto- 
plasm of  the  cells,  pink. 

The  streptococcus  pyogenes  is  the  commonest  germ  of 
puerperal  fever.  The  bacillus  typhosus  is  present  in  at  least 
25  per  cent,  of  cases  of  typhoid  fever  during  convalescence. 
The  diplobacillus  of  Friedlander  is  occasionally  present  in  the 
urine,  particularly  during  an  attack  of  pneumonia.  Other  un- 
usual pathogenic  urinary  bacteria  are  the  streptococcus  ery- 
sipelatis,  spirillum  of  relapsing  fever,  bacillus  of  glanders, 
anthrax  bacillus,  and  bacillus  of  ulcerative  endocarditis. 


PLATE   VIII. 


TUBERCLE  BACILLI  IN  URINARY  SEDIMENT. 

.  (After  v.  Jaksch.) 


URINE. 


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478  CLINIC  CHEMISTRY. 


THE  URINE  IN  THE  DIAGNOSIS  OF  NON- 
URINARY  DISEASES. 

We  judge  most  certainly  the  condition  of  a  living  organ- 
ism by  comparing  its  intake  and  its  output.  The  urine  is  the 
chief  index  of  metabolism  in  the  human  body,  and  its  qualita- 
tive and  quantitative  examination  furnishes  evidence  of  the 
greatest  practical  value. 


SPECIFIC   INFECTIONS. 

During  the  febrile  stage  of  all  fevers  the  urine  is  dimin- 
ished in  quantity  and  highly  acid.  The  sp.  gr.  shows  a  relative 
increase,  owing  to  the  absolute  excess  of  urea  depending  on 
augmented  tissue-waste.  Uric  acid  is  increased  proportionately 
even  more  than  urea,  and  uratic  deposits  are  common.  The 
excretion  of  chlorids  and  phosphates,  except  in  spotted  fever, 
is  diminished  until  the  beginning  of  convalescence.  Pigmenta- 
tion is  deepened  because  of  hemolytic  changes,  and  bile-pig- 
ment is  not  infrequently  present,  particularly  in  small-pox. 
Hemoglobinuria  is  indicative  of  decided  destruction  of  red 
blood-corpuscles;  it  accompanies  severe  infections,  and  is  a 
valuable  premonitory  sign  of  scarlatinal  hematuria  and  nephri- 
tis. Albuminuria  is  observed  at  some  time  in  the  majority  of 
cases  of  fevers  generally,  but  is  usually  slight  in  quantity  unless 
nephritis  complicates.  Peptonuria  is  occasionally  noted,  par- 
ticularly in  pyemia  and  cerebro-spinal  meningitis,  and  a  trace 
of  glucose  is  not  uncommon.  Hyaline  casts  are  frequent,  even 
without  supervening  nephritis — in  the  event  of  which  we 
find  also  epithelial,  red  blood-,  leucocyte,  and  granular  casts. 
Chronic  pyelitis  is  a  more  frequent  sequel  of  infectious  diseases 
than  is  chronic  nephritis. 

The  special  color  test  of  typhoid  fever  known  as  Ehrlich's 
diazo  reaction  has  been  ranked  by  good  authority  as  of  equal 
value  with  Widal's  agglutination  test.  It  occurs  a  day  or  two 
earlier  (fifth  to  ninth  day  usually)  than  does  the  serum-reaction, 
and  serves  quantitatively  for  prognosis,  whereas  the  serum- 
reaction  is  said  to  have  no  prognostic  significance;  the  diazo 
reaction  may  be  absent  throughout  the  course  of  very  mild  cases 
of  enteric  fever.  This  reaction  is  of  special  use  in  differen- 
tiating typhoid  from  simple  enteritis  and  allied  complaints.  It 
is  likewise  met  with  in  miliary  tuberculosis  (usually  not  till  the 
third  week),  carcinoma,  and  in  severe  cases  of  measles,  scarla- 
tina, erysipelas,  and  pyemia,  as  also  in  cases  of  ordinary  phthisis 


PLATE   IX. 


Fig  2 


Fig.  3 


CHARACTERISTIC  MICROSCOPIC  SEDIMENTS. 


Fig.  i.  Acute  Nephritis. 
Fig.  3.  Pyelitis. 


Fig.  2.  Chronic  Diffuse  Nephritis. 
Fig.  4.  Cystitis. 


URINE.  479 

which  are  rapidly  progressing  to  a  fatal  termination.     In  all 
these  instances  its  occurrence  is  chiefly  an  item  of  prognosis. 

The  Ehrlich  reaction  depends  upon  the  red  color  produced 
by  the  action  of  diazo-benzol-sulphonic  acid,  in  the  presence  of 
excess  of  NH4OH,  on  an  unknown  chromogen  in  the  urine  of 
typhoid  and  other  diseases.  Two  solutions  are  required  and 
should  be  kept  in  a  dark  place.  The  first  consists  of  10  c.c. 
HC1  with  200  c.c.  of  a  saturated  aqueous  solution  of  sulphanilic 
acid.  The  second  is  a  0.5-per-cent.  aqueous  solution  of  sodium 
nitrite,  made  as  fresh  as  possible.  The  reaction  between  these 
two  solutions  may  be  represented  as  follows: — 

W  <sc3k  +  HNO*  =  C'H*  <  so3  >  N  +  2^° 

To  apply  the  test  mix  100  parts  of  the  first  solution  with  1 
part  of  the  second,  add  an  equal  volume  of  urine,  shake  well, 
and  allow  an  excess  of  NH4OH  to  run  slowly  down  the  side  of 
the  tube.  If  the  reaction  is  positive,  the  foam  will  be  colored 
pink  and  the  urine  crimson.  The  color  of  the  foam  is  the  most 
essential  feature,  since  all  febrile  urines  give  an  orange  color 
with  the  test  solution.  If  the  mixture  is  poured  into  a  porce- 
lain dish  containing  water,  a  salmon-red  color  is  obtained  when 
the  reaction  is  positive,  while  a  yellow  or  orange  color  is  nega- 
tive. 

HEMIC   AND   CIRCULATORY   DISORDERS. 

The  relative  value  of  the  vis  a  tergo  is  the  all-important 
factor  in  the  causation  of  the  urinary  changes  of  circulatory 
origin.  When  cardiac  hypertrophy  exists,  and  compensation  is 
maintained,  there  is  absolute  increase  of  both  the  water  and 
the  solids  of  the  urine.  Failing  compensation  is  marked  and 
measured  by  decrease  of  the  solid  ingredients  and  by  the  pres- 
ence of  albumin  and  hyaline  casts,  both  of  which  may  be  made 
to  disappear  for  a  time  under  the  administration  of  digitalis 
and  other  cardiac  tonics.  Much  the  same  picture  as  to  the 
urine  presents  itself  in  the  secondary  cardiac  dilation  of  valvu- 
lar disease,  and  in  arteriosclerosis  and  the  various  myocardial 
degenerations. 

Concerning  blood-changes  proper,  hematuria,  apparently 
spontaneous,  is  of  rather  common  occurrence  in  purpura  hem- 
orrhagica,  scurvy,  and  hemophilia.  A  pale,  abundant  urine, 
deficient  in  normal  solids,  is  a  feature  of  chlorosis  and  anemias. 
In  progressive  pernicious  anemia  indicanuria  is  a  prominent 
sign.  A  small  amount  of  albumin  may  be  encountered  in  any 
of  the  blood  dyscrasias  as  well  as  in  degenerative  lesions  of  the 


480  CLINIC  CHEMISTRY. 

ductless  glands.  Remembering  the  nucleinic  origin  of  uric  acid, 
a  great  excess  of  this  ingredient  in  the  urine  of  leukemia  is  not 
surprising.  Ulcerative  endocarditis  and  hidden  pyemic  foci  may 
discover  themselves  first  by  renal  infarcts,  with  sudden  pro- 
nounced albuminuria  and  blood-  and  pus-  casts. 

RESPIRATORY  DISEASES. 

The  chlorids  show  a  reduction  in  all  dyspneic  conditions, 
particularly  in  pneumonia  and  capillary  bronchitis.  The  ex- 
cessive excretion  of  chlorids  following  retention  is  a  more  def- 
inite sign  of  resolution  than  even  the  fall  of  temperature  by 
crisis  or  lysis.  Urea  and  sulphates  are  markedly  increased  ex- 
cept in  grave  cases,  and  the  urates  are  enormously  augmented. 
Albuminuria  is  present  in  nearly  one-half  of  all  cases  of  pneu- 
monia, and  these  yield  a  mortality  three  times  as  great  as  in 
non-albuminuric  patients.  Albumosuria  or  peptonuria  is  a 
distinctive  feature  of  the  absorption  stage  in  pneumonia  and 
pleurisy  with  exudation.  The  urine  of  phthisis  is  very  variable. 
It  is  usually  increased  in  quantity  till  near  the  fatal  end.  Albu- 
minuria is  the  rule,  but  the  quantity  is. slight  except  in  amyloid 
renal  lesions,  which  are  comparatively  rare.  The  urine  of  em- 
physema is  also  likely  to  contain  albumin,  owing  to  circulatory 
obstruction. 

GASTRO-INTESTINAL  DISEASES. 

In  organic  disease  of  the  stomach  and  intestines  the  urine, 
as  a  rule,  is  diminished  in  quantity,  the  diminution  amounting 
to  suppression  at  times  in  the  various  forms  of  cholera,  in  ap- 
pendicitis, and  in  acute  obstruction.  The  reaction  is  frequently 
neutral  or  alkaline,  with  resulting  precipitation  of  earthy  phos- 
phates, or  "phosphaturia."  The  normal  digestive  curve  of  acid- 
ity is  always  deepened  in  gastrosuccorrhea,  but  is  absent  in 
atrophic  gastritis  and  cancer  of  the  stomach.  The  chlorids  are 
deficient  in  carcinoma  ventriculi  and  in  dilation  with  gastro- 
succorrhea. Intestinal  indigestion  is  characterized  by  deposits 
of  urates  and  oxalates.  A  trace  of  albumin,  attributable  to 
autointoxication,  is  not  seldom  to  be  found,  and  peptonuria  is 
often  present  in  ulcerative  conditions.  Next  to  pus,  an  excess 
of  "indican"  is  the  most  familiar  feature  of  pathologic  urines. 
This  indicanuria  signifies,  as  a  rule,  albuminous  putrefaction  in 
the  alimentary  tract,  and  the  indications  for  laxatives  and  intes- 
tinal antiseptics  are  plain.  In  acute  or  chronic  intestinal  ob- 
struction the  excess  of  indican  is  apt  to  be  enormous,  and  it  is 
likewise  marked  in  general  peritonitis.  Hydrothionuria  nat- 
urally gives  rise  to  a  suspicion  of  fecal  fistula,  but  the  same 


URINE.  481 

sewer-gas  odor  may  be  developed  by  certain  micro-organisms 
introduced  per  vias  naturales. 

* 

HEPATIC   AND   PANCREATIC   LESIONS. 

In  all  liver  lesions  the  urine  is  highly  acid  and  deeply 
colored.  Bile-pigment  is  commonly  present  in  considerable 
amount.  Urea  is  more  or  less  diminished,  being  nearly  absent 
and  replaced  by  ammonia  in  acute  yellow  atrophy.  Uric  acid 
is  increased,  while  the  chlorids  are  diminished  in  direct  propor- 
tion with  ascites.  Albumin  is  seldom  noted  except  in  cases 
secondary  to  cardiac  lesions  and  in  syphilitic,  tubercular,  and 
amyloid  livers.  A  trace  of  sugar  is  not  infrequent  in  liver  dis- 
orders generally.  In  obstructive  jaundice  choluria  is  evident 
both  before  and  after  the  appearance  of  icterus  in  the  skin.  The 
conjugate  sulphates  are  much  increased  in  obstructive  jaun- 
dice; the  total  sulphates  diminished  in  the  non-obstructive 
form.  The  choluria  of  cholelithiasis  is  of  distinct  service  in 
differentiating  hepatic  from  renal  colic  and  other  abdominal 
pain.  Leucin  and  tyrosin  are  occasionally  noted  in  various 
hepatic  affections  as  well  as  in  defective  intestinal  digestion, 
but  they  are  much  more  abundant  in  acute  yellow  atrophy.  A 
striking  character  of  the  later  stages  of  hepatic  cirrhosis  is  the 
coincidence  of  a  urine  dark  in  color  and  light  in  weight:  always 
a  sign  of  grave  import. 

Chronic  pancreatitis  is  marked  by  polyuria,  glycosuria,  and 
lipuria.  There  may  be  albumin  or  glucose  in  the  urine  of  pa- 
tients with  pancreatic  cysts.  Lipuria  is  also  observed  in  cancer 
of  the  pancreas,  and  diabetes  mellitus  may  supervene. 

OSSEOUS,  ARTICULAR,  AND   CONSTITUTIONAL  DISEASES. 

The  urine  of  acute  articular  rheumatism  is  typically  py- 
rexial,  with  high  color,  density,  and  acidity;  great  excess  of 
urea,  sulphates,  and  urates;  and  diminished  chlorids.  Albu- 
minuria  is  slight  and  transient.  The  most  marked  feature  of 
gouty  urine  is  the  nearly  constant  reduction,  from  retention, 
of  uric  acid  and  phosphates,  with  periodic  storms  of  excessive 
excretion  immediately  following  acute  exacerbations.  This 
condition  is  frequently  associated  with  oxaluria  and  with 
chronic  interstitial  nephritis.  In  tubercular  joint  disease,  with 
abscess-formation,  the  presence  of  peptonuria  may  aid  in  a 
correct  diagnosis.  In  gonorrheal  arthritis  careful  examination 
of  the  urethral  secretions  will  usually  reveal  the  gonococci. 
Rachitis  and  osteomalacia  are  both  distinguished  by  great  ex- 
cess of  earthy  phosphates;  chronic  articular  rheumatism  and 


482  CLINIC  CHEMISTRY. 

diffuse  periostitis,  by  less  marked  increase.  Fat  in  the  urine  is 
commonly  observed  after  fracture  of  the  long  bones,  and  the 
return  of  the  earthy  phosphates  to  a  normal  daily  amount,  after 
previous  excess,  is  a  certain  indication  that  bony  union  is  com- 
plete. Glycosuria  often  obtains  in  acromegaly.  The  urine  of 
lithemia  is  scanty,  sharply  acid,  high  colored,  and  uratic  during 
the  attacks.  There  is  occasionally  slight  albuminuria,  with 
cylindroids  and  hyaline  casts.  The  lithemia  of  infants  is  mani- 
fested by  a  deposit  of  red  sand  on  the  diapers.  Muscular  rheu- 
matism is  sometimes  accompanied  by  oxaluria.  In  simple 
atrophy,  or  marasmus,  the  urine  is  often  milky  from  white 
urates,  fat,  and  mucus,  and  albumin  or  sugar  may  be  present. 
Albumosuria  has  been  noted  particularly  in  sarcomatosis  of 
the  ribs,  sternum,  and  other  bones. 

NERVOUS   DISEASES. 

Hysteria  is  noted  for  the  large  amount  of  watery  urine 
which,  as  a  rule,  accompanies  or  follows  the  seizure;  but,  on  the 
other  hand,  there  may  be  suppression  lasting  for  days.  Tran- 
sient polyuria  is  also  observed  after  epileptic  fits,  attended  at 
times  by  a  little  albumin.  In  neurasthenia  the  urine  is  con- 
stantly deficient  in  normal  solids.  In  melancholia  the  urine  is 
often  deficient  in  quantity,  and  of  high  sp.  gr.  Oxaluria  is  apt 
to  show  itself  clinically  by  intestinal  dyspepsia,  lumbar  aching, 
and  nervous  irritability  and  depression.  Phosphaturia  is  a  fre- 
quent accompaniment  of  nervous  debility.  In  chorea  we  find 
an  increase  both  of  urea  and  of  phosphates.  Migraine  is  marked 
toward  the  close  of  the  attack  by  an  abundance  of  uric  acid  and 
allied  products.  Glycosuria  is  of  common  occurrence  in  medul- 
lary lesions.  Surgical  shock,  particularly  when  due  to  rectal 
or  genito-urinary  operations,  is  likely  to  be  joined  with  urinary 
suppression  or-  retention.  Retention,  usually  with  overflow,  is 
usually  present  likewise  in  organic  spinal  lesions.  In  meningitis 
and  other  high-grade  nerve-inflammations  the  earthy  phos- 
phates are  greatly  in  excess.  The  three  forms  of  diabetes — 
insipidus,  mellitus,  and  phosphatic — have  already  been  men- 
tioned. 

SKIN  AFFECTIONS. 

Obviously  a  study  of  the  urine  is  not  often  needed  in  skin 
diseases  proper,  so  far  as  concerns  diagnosis,  yet  in  seeking  the 
primary  cause  we  shall  sometimes  get  valuable  points  concern- 
ing defective  metabolism  and  autointoxication.  Eczema,  pso- 
riasis, and  a  number  of  other  disorders  seem,  from  the  urine, 
to  be  forms  of  lithemia.  Hematuria  is  frequent  after  severe 
burns  and  occurs  occasionally  in  Raynaud's  disease. 


URINE.  483 

SURGICAL   CONDITIONS. 

Abdominal  tumors  may  and  often  do  give  rise  by  press- 
ure to  albuminuria.  The  occurrence  of  melaninuria  is  nearly 
pathognomonic  of  melanotic  growths.  In  perirenal  and  peri- 
vesic  inflammation  the  nuclei  of  the  cells  from  these  sites  are 
often  multiple.  Internal  pus-formation  in  any  part  of  the  body 
is  indicated  by  peptonuria,  the  later  disappearance  of  which 
shows  that  the  abscess  has  discharged  externally  or  is  encap- 
sulated. The  resorption  of  hemorrhagic  exudations  is  revealed 
by  hemoglobinuria.  A  considerable  relative  increase  of  urinary 
nitrogen  over  phosphoric  oxid  is  said  to  be  a  sign  of  malignancy. 

DIFFERENTIATION  OF  URINARY  CALCULI. 

Heat  a   portion   of   the   powdered   concretion   on  platinum-foil. 

I.  The  powder  burns: 

1.  Without  a  flame: 

Uric  acid:  inurexid  test;  no  NH3  odor  on  treating  with  KHO;  over 
three-fourths  of  cases;  reddish  or  yellow-brown  and  tuberculated. 

Ammonium  urate:  murexid  test;  strong  odor  of  NH3  on  treating 
with  KHO;  light  gray;  infancy. 

Xanthin:  yellow  residue  on  evaporating  with  HN03  turns  orange 
with  KHO,  red  on  warming;  very  rare. 

2.  With  a  flame: 

Cystin:  transient,  pale-blue  flame;  sharp  odor;  powder  dissolved  in 
ammonia  yields  six-sided  plates  on  evaporation. 

Urostealith:  steady  yellow  flame  with  odor  of  resin;  fatty  and  sol- 
uble in  alcohol  or  ether;  soft,  friable,  brown  or  yellow. 

Fibrin:  steady  yellow  flame  with  odor  of  burnt  feathers;  insoluble 
in  alcohol  or  ether,  soluble  in  hot  KHO. 

II.  The  powder  does  not  burn.     Treat  with  HC1: 

1.  Effervesces  =  calcium  carbonate:    small,  smooth,  spheric,  gray  or 

bronze;  very  rare  in  humans. 

2.  Does  not  effervesce: 

Effervesces  on  heating  gently  with  HC1  =  calcium  oxalate:  very 
hard  and  brittle  --  large,  dark,  rough,  "mulberry"  calculi,  or 
small,  smooth,  rounded,  dark-gray  "hemp-seed"  calculi;  often  in 
alternating  layers  with  uric  acid,  and  sometimes  crusted  with 
phosphates. 

Odor  of  NH3  on  treating  with  KHO  =  triple  and  earthy  phosphates: 
soluble  in  acetic  acid  and  fusible;  alkaline  urine;  gray-white  and 
friable. 

Faint  or  no  odor  of  NH3  on  treating  with  KHO  =  earthy  phos- 
phates: chalky,  rounded,  or  irregular;  alkaline  urine  of  elderly 
persons. 

POISONS. 

Corrosive  poisoning  in  general  is  attended  by  scantiness  or 
suppression  of  the  urine,  and  the  same  is  true  of  arsenic  and 
belladonna  in  tox"ic  doses.  In  acute  phosphorus  poisoning  the 
urine,  if  not  suppressed,  is  bloody,  fatty,  and  albuminous,  and 


484  CLINIC  CHEMISTRY. 

contains  crystals  of  leucin  and  tyrosin.  Turpentine,  cantharis, 
and  other  renal  irritants;  illuminating  gas,  arsenious  vapors, 
coal-tar  derivatives,  and  other  corpuscle-destroying  agents  fre- 
quently give  rise  to  hematuria  or  hemoglobinuria.  The  black- 
ish-green color  of  the  urine  and  characteristic  odor  of  carbolic 
acid  are.  highly  suggestive  of  poisoning  by  this  drug,  which  is 
not  seldom  the  result  of  its  free  and  careless  topic  use. 

Chronic  mineral  poisoning  is  characterized,  as  a  rule,  by 
scanty  urine  and  deficient  urinary  solids.  Albuminuria  is  fre- 
quent, and  chronic  interstitial  nephritis  is  a  not  uncommon 
sequel.  The  detection  of  lead,  mercury,  arsenic,  copper,  etc., 
in  the  greatly  concentrated  and  oxidized  urine  furnishes  incon- 
trovertible evidence  of  the  causa  morbi.  This  test  is  most  cer- 
tain when  preceded  by  the  administration  of  potassium  iodid 
for  several  days. 

QUESTIONS   ON   CLINIC   CHEMISTRY. 

1.  How  may  a  milk  have  been  skimmed  and  watered  and  yet  show 
a  normal  sp.  gr.? 

2.  Explain  how  the  amount  of  free  gas  in  the  ureometer  may  be 
greater  at  first  than  after  standing  fifteen  or  twenty  minutes. 

3.  Write    equation    for   reaction    between    uric    acid    and    disodic 
hydric  phosphate. 

4.  Explain  formation  of  bubbles  sometimes  noticed  in  the  nitric- 
acid  test  for  albumin. 

5.  How  prove  by  the  urine  that  a  patient  has  been  taking  bromids 
or  iodids? 

6.  Why  is  the  appearance  of  leucin  and  tyrosin  accompanied  by 
a  marked  reduction  of  urea? 

7.  Why  do  K  salts  exceed  Na  salts,  reversing  the  normal  ratio, 
in  urine  during  starvation? 

8.  What  effect  does  drinking  lemonade  have  on  urinary  acidity? 

9.  Is  lithemic  urine  likely  to  be  more  irritating  in  summer  or  in 
winter? 

10.  What  is  the  significance  of  freshly  passed  ammoniacal  urine? 

11.  What   object   in    adding   HN03    before   AgNO3    in    determining 
chlorids? 

12.  What  information  does  the  urine  furnish  concerning  digestion? 

13.  A  drop  of  urine  containing  globulin  shows  an  opalescent  trail 
when  dropped  into  distilled  water.     Explain. 

14.  How  determine  the  amount  of  acid  salts  in  gastric  juice? 

15.  Name  five  drugs  which  taken  internally  may  give  a  color  to 
the  urine  like  that  of  blood. 

16.  Why  does  blood  from  the  kidney  render  the  urine  smoky? 

17.  If  one  gets  an  albumin-like  ring  which  disappears  on  heating, 
what  is  it? 

18.  Explain   the    color-changes   in   the    copper   reduction    tests    for 
sugar. 

19.  What  are  the  most  certain  evidences  of  kidney  disease? 

20.  How  diagnose  renal  insufficiency? 

21.  Write   equation   for  the  alkaline  fermentation   of  urine. 


QUESTIONS.  485 

22.  In  what  disease  is  the  sp.  gr.  abnormally  high  with  increased 
quantity  of  urine?     Explain. 

23.  In  what  diseases  are  the  sp.  gr.  and  quantity  of  urine  both  at 
times  abnormally  low?     Explain. 

24.  What  is  the  clinic  significance  of  indicanuria? 

25.  Mention  five  points  of  distinction  between  a  sediment  of  urates 
and  one  of  phosphates. 

26.  Explain  the  relation  of  the  night  excretion  to  the  fact  that  the 
urine  is  especially  acid  mornings. 


APPENDIX. 


SOLUBILITY  OF  COMMON  DEUGS  AT  15°  C. 


EXPLANATION. — s.  =  soluble  ;  ins.  =  insoluble  ;  f.  s.,  v.  s.,  and  sp.  =  freely,  very,  sparingly 
soluble  ;  aim.  =  almost ;    mis.  =  miscible  ;  dec.  =  decomposed. 


WATEU. 
PAKTS. 

ALCOHOL. 
PARTS. 

1 

ins. 

200 

10 

Acid,  benzole  

500 

3 

25 

15 

s. 

s. 

20 

V    S 

v  sp 

s. 

citric  

0.75 

1 

100 

4.5 

ins 

g 

450 

2  5 

tannic    

6 

0.6 

0.7 

2.5 

f  s 

f  s 

Aloin                .......           >    . 

60 

25 

Alum        

10  5 

ins. 

"      burnt     .    .           ...    

20 

ins. 

5 

28 

bromid           ....                .    , 

1  5 

150 

carbonate  ...        .    .        

4 

dec 

3 

1.5 

iodid                      ...                       ... 

1 

9 

valerianate       .    .       .               . 

v  s 

v  s 

8 

5 

Antimony  and  potassium  tartrate  
"         oxid                   

17 

ins 

ins. 
ins 

1 

1 

Apiol                                           .    .    . 

6.8 

50 

Adstol  

ins. 

sp. 

Arsenic  iodid                          ....               ..... 

35 

10 

Arsenous  oxid    ...        

30  to  80 

sp 

Asafetida             ..           ...           

eniuls 

60$> 

sp. 

0.3 

600 

v  s 

0  4 

6  5 

Balsam  of  copaiba    

ins. 

10 

"         "    Peru     ,    

aim.  ins. 

5 

"  Tolu     

aim.  ins. 
ins 

v.  s. 

g 

ins 

g 

§ 

g 

Bismuth  and  ammonium  citrate  
u        citrate      .           .           

ins. 

V    8 

ins. 

SP 

ins 

•F' 

ins 

ins. 

ins 

Bromoform      .           

300 

v   s 

(489) 


490  APPENDIX. 

SOLUBILITY  OF  COMMON  DRUGS  AT  15°  C.  (Continued). 

EXPLANATION.— s.  =  soluble;  ins.  =  insoluble  ;  f.  s.,  v.  s.,  and  sp.  =  freely,  very,  sparingly 
soluble;  aim.  =  almost ;  mis.  =  miscible  ;  dec.  =  decomposed. 


WATER. 

PARTS. 

ALCOHOL. 
PA  KTS. 

Caffein      .                       .... 

80 

0.7 
ins. 
1.5 
s. 
7 
s. 
ins. 
aim.  ins. 
1300 
aim.  ins. 
ins. 
ins. 
v.  s. 
10 
170  ~ 
100 
200 
v.  s. 

33 

1 
ins. 
8 
aim.  ins. 
ins. 
ins. 
ins. 
ins. 
f.  s. 

V.  S. 

ins. 
ins. 
v.  s. 
2.5 
f  .  s. 

V.  S. 
V.  S. 

dec. 
sp. 
70 
6 
3.5 
v.  s. 
s. 
2 
135 

ins. 

s. 

V.  S. 

s. 
s. 
ins. 
sp. 
f.  s. 
s. 
2 

337 

s. 
s. 
3 
14 

s. 
s. 

s. 
s. 

carbonate             

phosphate                

Camphor  ...        

"         monobromated      

Chalk                                              ...... 

Chloral  hydrate          

Chloralamid                ......            . 

Chloral  ose    

Chloretone  .                                                          . 

Chloroform          

Chromic  oxid                  .        .    .        

sp. 
100 
70 
0.5 
80 
s. 
2 
15 
sp. 
2.6 
s. 
150 
ins. 
mis.(2i#) 
ins. 
s. 
ins. 
ins. 
7 
0.5 
ins. 
s. 
ins. 
ins. 
10 
28 
aim.  ins. 
ins. 
sp. 
ins. 

Cocain  hydrochlorate    

"       sulphate                 . 

Cotarnin  hydrochlorate  (stypticin)          

Creasote   .                        .    .                   ........ 

Diabetin  (levulose)      .        

Ethyl   bromid     

"       iodid    

"        beta-  

SOLUBILITY. 


491 


SOLUBILITY  OF  COMMON  DKUGS  AT  15°  C.  (Continued). 

EXPLANATION.— s.  =  soluble;  ins.  =  insoluble;  f.  s.,  v.  s.,  and  s'p.  =  freely,  very,  sparingly 
soluble  ;  aim.  =  almost ;  mis.  =  miscible ;  dec.  =  decomposed. 


WATER. 
PARTS. 


Ferric  and  ammonium  citrate v.  s.  ins. 

"   potassium  tartrate v.  s.  ins. 

"   quinin  citrate          s.  ins. 

"   strychnin  citrate v.  s.  sp. 

chlorid      v.  s.  v.  s. 

citrate s.  ins. 

hydrate ins.  ins. 

hypophosphite sp.  ins. 

lactate      . 40  aim.  ins. 

phosphate v.  s.  ins. 

pyrophosphate v.  s.  ins. 

sulphate       1.8  ins. 

tartrate v.  s.  ins. 

valerianate      ins.  f.  s. 

Fluorescein         s. 

Formaldehyd      v.  s. 

Fuchsin        s. 

Glycerin  ..... f.  s.  f.  s. 

Gold  and  sodium  chlorid      . !       v.  s.  sp. 

Guaiacol       ,    .    .  85  f.  s. 

"        carbonate ins.  sp. 

Heroin  hydrochlorate s. 

Holocain  hydrochlorate 50  6 

Homatropin  hydrobromate .    .    .  !         10  133 

Hydrastin  hydrochlorate f.  s.  f.  s. 

Hydrastinin  hydrochlorate 1  3 

Hyoscin  hydrobromate 4  15 

Ichthyol I       v.  s.  ins. 

lodin        j       5000  10 

lodoform      ins.  80 

lodol ins.  3 

Kairin      6  20 

Kryofin 600  f.  s. 

Lactophenin 500  9 

Lanolin            mis.  2  80 

Lime         „ 750  ins. 

Lithium  benzoate      4  12 

"        bromid         v.  s.  v.  s. 

"        carbonate 80  ins. 

citrate          2  sp. 

"        salicylate v.  s.  v.  s. 

Losophan sp.  s. 

Lycetol s. 

Lysol .  f.  mis.  v.  s. 

Magnesium  carbonate aim.  ins.  ins. 

oxid            aim.  ins.  ins. 

sulphate i        1.5  ins. 

Manganese  dioxid ins.  ins. 

sulphate 11  ins. 


ALCOHOL. 
PARTS. 


492 


APPENDIX. 


SOLUBILITY  OF  COMMON  DEUGS  AT  15°  C.  (Continued}. 

EXPLANATION.— s.  =  soluble;  ins.  =  insoluble;  f.  a.,  v.  s.,  and  sp.  =  freely,  very,  sparingly 
soluble  ;  aim.  =  almost ;  mis.  =  miscible  ;  dec.  =  decomposed. 


WATER. 
PARTS. 

ALCOHOL. 
PARTS. 

Menthol                                  .            ... 

SP 

V    S 

16 

3 

"         cy  tin  id                        .                   

13 

15 

"         iodid(red)     

aim.  ins. 

130 

"        oxid                     .... 

ins 

ins 

ins 

ins 

Mercurol  (10^  nuclein)  ....                

s 

ins. 

ins. 

ins. 

aim.  ins. 

ins. 

ins. 

ins. 

530 

s. 

4  vol. 

35  vol. 

sp. 

50 

Morphin  acetate             

12 

68 

24 

63 

"        sulphate  

24 

702 

Naphtalen                       .    .           ... 

ins. 

15 

Naphtol,  beta-    .            

1000 

75 

Nosophen         

ins. 

ins. 

Oils,  fixed    

ins. 

ins. 

"     volatile   ...       .    .       

v.  sp. 

f.  s. 

Orexin  hydrochl  orate    

v   s 

V    S 

Orthofonn                   ... 

sp 

ins. 

sp. 

ins. 

Paraldehyd      •                    •        ...            

10 

g 

Pelletierin  tannate    •    •                   . 

700 

80 

100 

ins 

Petrolatum  .......        

ins 

ins 

Phenacetin  

1700 

20 

Phenocoll  hydrochlorate      .        

16 

Phosphorus                             

ins. 

350 

Physostigmin  (eserin)  salicylate    .    .        .    .           .    . 

150 

12 

240 

9 

v   s 

v.  s 

Piperazin     

V.  S. 

aim   ins 

30 

2  3 

21 

"         iodid    

2000 

v   sp 

2 

v   sp 

"         oxid                      

ins 

ins 

Potassium  acetate  ... 

0  4 

1  9 

1  4 

al  m   i  ns 

3  2 

aim    ins 

bitartrate     

200 

v   sp 

bromid     

1  6 

200 

1 

ins 

chlorate    

16  5 

v   sp 

0  6 

cyanid  

2 

sp 

SOLUBILITY. 


493 


SOLUBILITY  OF  COMMON  DRUGS  AT  15°  C.  (Continued). 

EXPLANATION. — s.  =  soluble;  ins.  =  insoluble;  f.  s.,  v.  s.,  and  sp.  =  freely,  very,  sparingly 
soluble  ;  aim.  =  almost ;  mis.  =  miscible  ;  dec.  =  decomposed. 


WATER. 
PARTS. 

ALCOHOL. 
PARTS. 

10 

ins 

4 

ins. 

0.5 

2 

0  6 

7  5 

0  8 

18 

4 

aim   ins 

18 

dec 

4 

SD 

f  s 

op. 
SD 

tartrate            •            •        ... 

0  7 

aim    ins 

Protaro-ol  (8f/c  A<rj    

s 

75 

12 

niis 

I 

100 

s 

Quinin                 ...                       .    .    .    .        .... 

1670 

6 

10 

32 

54 

0  6 

34 

3 

"      sulphate             ...           .    . 

740 

65 

100 

5 

ins 

f  s 

2 

§ 

§ 

400 

30 

ins 

15 

30 

60 

250 

v   s 

Salol         

aim   ins. 

10 

ins 

V    S 

SD 

40 

Scopolamin  hydrobromate       ....                    . 

4 

15 

20 

0  8 

°6 

"      oxid           

v   sp 

ins 

5  hot 

2 

3 

30 

4 

v    SD 

1  8 

v.  c-p. 

45 

12 

ins 

4 

72 

'        borate  (borax)      .    .        

25 

ins 

'        bromid  

2 

16 

g 

1  6 

ins 

1  1 

100 

'        chlorid       

2  8 

aim   ins 

s. 

1  7 

v  s 

1 

30 

494 


APPENDIX. 


SOLUBILITY  OF  COMMON  DRUGS  AT  15°  C.  (Concluded). 

EXPLANATION. — s.  =  soluble  ;  ins.  =  insoluble  ;  f.  s.,  v.  s.,  and  sp.  =  freely,  very,  sparingly 
soluble;  aim.  =  almost ;  mis.=  miscible  ;  dec.  =  decomposed. 


WATER. 
PARTS. 


ALCOHOL. 
PARTS. 


Sodium  hyposulphite 1.5 

iodid       0.6 

nitrate        ,  1.3 

phosphate 6 

pyrophosphate 12 

salicylate   . 1.5 

sulphate 2.8 

sulphite 4 

sulphocarbolate 6 

Strontium  bromid      v.  s. 

iodid      v.  s. 

lactate 4 

Strychnin  sulphate 10 

Sugar,  cane-         0.5 

"       milk- 6 

Sulphonal 450 

Sulphur ins. 

Suprarenal  extract f.  s. 

Tannalbin ins. 

Tannigen ins. 

Terebene ins. 

Terpin  hydrate 250 

Thallin  sulphate 7 

Thiocol s. 

Thiol mis. 

Thymol 1200 

Trional 320 

Turpentine  (rectified  oil) ins. 

Uranium  nitrate s. 

Urethan 1 

Urotropin  (formin) s. 

Veratrin sp. 

Xeroform  (tribromphenol  bismuth) ins. 

Zinc  acetate 3 

bromid v.  s. 

carbonate ins. 

chlorid 0.5 

iodid v.  s. 

oxid ins. 

phosphid ins. 

sulphate 0.6 

sulphocarbolate 5 

valerianate 120 


ins. 

1.8 
sp. 
ins. 
ins. 
6 

ins. 

sp. 

150 

v.  s. 

V.  S. 

s. 

60 
175 
ins. 

50 
ins. 

ins. 

s. 

1 

10 
100 
sp. 
sp. 

s. 

3 

s. 

0.6 
sp. 

3 

ins. 

36 

v.  s. 

ins. 

1 

V.  S. 

ins. 

ins. 

ins. 

5 

40 


ARITHMETIC  CONSTANTS.  495 


ARITHMETIC  CONSTANTS. 

1  Barrel  (U.  S.)  =31  '/,.  gallons  =  119.2  liters. 

1    Bushel  (U.  S.)  =  2150.42  cubic  inches  =  32  quarts  =  35.243  liters. 
1  Calorie  =  2.2  thermal  units  =  425.5  kilogrammeters  =  425,500  gram- 
meters  =  3077.6  foot-pounds. 
1  Centimeter  =  V100  meter  =  0.3937  inch. 
1  Cubic  Centimeter  =  1/1000  liter  =  16.23  minims  =  0.061  cubic  inch  — 

weighs  1  gram  at  4°  C. 
1  Cubic  Foot  =.   1728   cubic  inches  —  28316.085   cubic   centimeters  — 

weighs  62.32  Ibs.  avoirdupois  at  62°  F. 
1  Cubic  Inch  =  266  minims  =  16.386  c.c.  —  weighs  252.46  grains  or 

16.372  grams. 

1  Cubic  Meter  (stere)  =  1000  liters  =  35.315  cubic  feet. 
1  Dram  (Troy,  or  Apothecary)  =  60  grains  =  3.888  grams. 
1  Fluidram  =  60  minims  =  3.696  cubic  centimeters. 
1  Fluidounce    (imperial)    =  28.4  c.c.  =   1.7329  cubic  inches  —  weighs 

437  V2  grains  at  62°  F. 
1  Fluidounce   (U.  S.  wine  measure)  =  8  drams  =  480  minims  =  29.57 

c.c.  =  1.8047  cu.  in.  —  weighs  456  grains  or  29.57  grams. 
1  Foot  =  12  inches  =  144  line*  =  0.30479  meter. 
1  Foot-pound  =  0.138  kilogrammeter. 
1  Gallon   (imperial)   =  277.27  cubic  inches  =  4.543  liters  —  weighs  10 

pounds  (70,000  grains). 
1  Gallon  (wine)  =  8  pints  =  231  cubic  inches  =  3.785  liters  —  weighs 

8.34  pounds   (58,328  grains). 
1  Gallon  (solid)  =  268.8  cubic  inches. 
1  Grain  (Troy)  =  0.0648  gram. 

1  Gram  =  15.4323  Troy  grains  =  weight  of  1  c.c.  of  water  at  4°  C. 
1  Inch  =  12  lines  =  2.54  centimeters. 
1  Kilogram  =  1000  grams  =  32.1   Troy  ounces  =  2.2046  avoirdupois 

pounds  =  weight  of  a  liter  of  water. 
1  Kilogrammeter  =  7.233  foot-pounds. 
1  Liter  —  a  cubic  decimeter  =  1000  c.c.  =  33.8  fluidounces  =  1.056  wine 

quarts  =  61.027  cubic  inches. 
1  Meter  =  3.28086  feet  =  39.37043  inches  =  about  one  forty-millionth 

of  earth's  meridian. 
1  Millimeter  =  1000  micromillimeters  =  Viooo  meter  =  0.0393  inch  (about 

V»  inch). 

1  Minim  =  0.0616  c.c.  —  weighs  0.95  grain. 
1  Ounce   (Troy)  =  480  grains  =  31.1  grams. 
1  Ounce   (avoirdupois)   =  437.5  grains  =  28.35  grams. 
1  Pint   (imperial)  =  20  fluidounces  =  567.93  cubic  centimeters. 
1  Pint   (U.  S.  wine)  =  16  fluidounces  =  473.179  cubic  centimeters. 
1  Pound   (Troy)  =  12  ounces  =  5760  grains  =  0.37324  kilogram. 
1  Pound   (avoirdupois)  =  16  ounces  =  7000  grains  =  0.45359  kilogram. 
1  Quart  (imperial)    =  40   fluidounces   =  69.97   cubic   inches  =   1.1358 

liters. 
1  Quart  (wine  measure)  =  32  fluidounces  =  58.3  cubic  inches  =  0.9463 

liter. 

1  Square  Foot  =  144  square  inches  =  0.0929  square  meter. 
1  Square  Meter  =  10.7641  square  feet. 

1  Thermal  Unit  =  0.45  calorie  =  1390  foot-pounds  =  0.695  foot-ton. 
1  Ton  (avoirdupois)  =  2000  pounds  =  29167  Troy  ounces  =  907.2  kilo- 
grams. 


496  APPENDIX. 

1  Tonneau  =  1,000,000  grams  =  1000  kilos  =  2204.6  avoirdupois  pounds. 
1  Yard  =  3  feet  —  36  inches  =  0.9144  meter. 


EQUATIONS  OF  MANUFACTURING  CHEMISTRY. 

Aluminum. 

Chlorid   4A12O3  +  12C12  +  3C2  (at  red  heat)  =4A1,C18  +  6CO, 

Hydrate   K,A12(S04)4.24H2O  +  NaaC03  =  A12(HO)6  +  Na2SO~4 

+  K2SO4  +  CO.,  +  2H2S04  +  16H2O  +  3H2 

Potash  Alum H2Al2Si2O8  (shale)  +  3HJ3O4  (hot)   +K,S04  =  Ala- 

K2(S04)4  +  4H20  +  2Si02 

Sulphate AI2(HO)0  +  3H2S04  =  A12(SO4)3  +  6H20 

Ammonium. 

Ammonia  (for  me- 
dicinal purposes)  .2NH4C1  +  Ca(HO)2  =  CaCl,  +  2NH3  +  2H20 

Bromid   NH4OH  +  HBr  =  NH4Br  +~  H2O 

Carbonate    2(NH4)2SO4  +  2CaC03    (heated   in   iron  retort)    = 

NH4HC03.NH4NH.,CO2    (official   carbonate)    + 
NH3  +  H20  +  2CaS04 

Chlorid   NH4OH    (ammoniacal   water  from   gas-works)    + 

CaO  =  NH3  -k  Ca  ( HO )  2.    NH3  +  HC1  =  NH4C1 

lodid  NH4OH  +  HI  =  NH4I  +  H20 

Nitrate   HNO8  +  NH4HO  =  NH4N03  +  H2O 

Sulphate 2NH4HO    (ammoniacal   gas    liquor)    +    H2S04  = 

(NH4)2S04  +  2H20 
Antimonium. 

Chlorid   Sb2S3  +  6HC1  =  2SbCl3  (solution)  +  3H2S 

Oxid    4SbCl3.5Sb4O6  +  6Na.,C03  =  6Sb4O0  +   12NaCl  + 

6C02 

Oxy  chlorid 24SbCl,  +  30H2O  =  4SbCl3.5Sb4O6  +  60HC1 

Oxysulphid    2Sb2S3  +  4NaHO  =  NaSb02  +  3NaSbS2  +  2H..O 

Tartrate  of  Anti- 
mony and  Potas- 
sium   4KHC4H406  +  Sb408  =  4KSbOC4H4O6  +  2H2O 

Arsenum. 

lodid As  +  I,  (rubbed  together  and  sublimated)  =  AsI3 

Oxid    As2  (ores  containing  As)  +  O3  (roasted  in  air)  = 

As203 
Barium. 

Chlorid BaS04  +  4C  (fusing)  =  BaS  +  4CO.     BaS  +  2HC1 

=  BaCl2  +  H2S 

Hydrate .BaC03   (heated  in  current  of  water)    +  H20  =  Ba- 

(H0)2  +  C02 

Nitrate BaC03  +  2HNO3  =  Ba(NO3)2  +  C02  +  H20 

Oxids    Ba(NO3)2   (heated  in  iron  crucible  till  red  fumes 

cease)  =  BaO  +  N2O5 
BaO  +  O  (heating  in  a  stream  of  dry  air  or  0  at 

450°  C.)  =BaO2 
Bismuth. 

Subcarbonate    2Bi(N03)3  +  Na2CO3  +  3H.O  =  (BiO),C03.H2O  + 

4HNO3  +  2NaN03 

Subnitrate Bi(N03)3  +  2H20  (4  parts  cold,  then  21  boiling)  = 

BiON03.H20  +  2HNO3 
Boron. 

Trioxid 2H3BO3  (heated  to  redness)  =  B203  +  3H,0 


EQUATIONS.  497 

Calcium. 

Bromid  2HBr  +  CaC03  =  CaBr2  +  CO2  +  H2O 

Cm-bid       CaO  +  30  (heated  in  electric  furnace)  =  CaC2  + 

CO 

(  arbonate    Na2CO3  +  CaCl2  =  CaCO3  +  2NaCl 

( 'hlorid  2HC1  +  CaCOs  (marble)  =  CaCl2  +  CO2  +  H20 

Hypochlorite Ca(HO)2  +  CJ2  =  CaOCl2  +  H2O 

Hypophosphite  .  . . .  3Ca(HO)o  +  2P4  -f  OH20   (warmed  to  40°)  =3Ca- 
(H2P02)2+2PH3 

Oxid    CaC03  (burned)  —  CaO  +  CO2 

Phosphate   3CaCl»  +  2NH4OH  +  2Na2HPO4.12H.,0:=Ca3(PO4)2 

+  2NH4C1  +  4NaCl  +  26H2O 
Sulphid CaSO4  +  2C  (charcoal  heated)  =  CaS  -f  2CO2 

Carbon. 

Dioxid CaCO,  (marble-dust)   +  2HC1  =  CaCl2  -f  H20  + 

C02 
Disulphid C  (charcoal)  +  S2  (heat  to  redness)  =  CS2 

Cerium. 

Oxalate    Ce2Cl6  +  3(NH4)aCA  =  Ce,(C2O4)3  +  6NH4C1 

Chromium. 

Sesquioxid K2Cr,O7  +  S  (heat)  =  K,S04  +  Cr2O3 

Trioxid K2Cr207  +  2H2S04  =  2Cr03  +  2KHSO4  +  H2O 

Copper. 

Arsenite   CuSO4  +  KH2As03  =  CuHAsO3  +  KHSO4 

Nitrate  3Cu  +  8HNO3  =  3Cu(N03)2  +  N2O2  +  4H2O 

Sulphate Cu  +  2H2SO4  =  CuSO4  +  S02  +  2H2O 

Gold. 

Chlorid  Au  +  C13  (nitrohydrochloric  acid)  =  AuCl3 

Hydrogen. 

Arsenate    AsaO8  +  2H2O  +  2HNO3  =  2H3As04  +  N2O3 

Bromid   3KBr  -f-  H3PO4  (heated  together)  =  3HBr  +  K3P04 

Chlorid  2NaCl  +  H.,S04  =  Na2SO4  +  2HC1 

Cyanid    K4Fe(CN)8  +  5H,SO4  =  6HCN  +  FeSO4  +  4KHSO4 

Dioxid Ba02  +  2HF  =  H2O2  +  BaF2 

Fluorid CaF2  -f  H2SO4  =  CaSO4  +  2HF 

lodid 2I2  +  2H,S  +  H,O  —  4HI  +  S2  +  H2O 

N  it  rate  KNO3  +  H,SO4  =  HNO»  +  KHSO4 

Orthoborate    Na2B407  +  2HC1  +  5H.,0  =  4H3BO3  +  2NaCl 

Phosphate   3P  +  5HN03  +  2H20  =  3H8P04  -f  5NO 

Salicylate NaC7H0O3  +  HC1  =  HC7ILO,  +  NaCl 

Sulphate 2S02  +  N2O4  +  2H,O  =  2H2SO4  +  N2O2 

Sulphid FeS  +  H«S04  =  FeSO4  +  H2S 

Sulphite   SO2  +  H2O  =  H2SO3 

Iron. 

Carbonate    Na2C03  +  FeSO4  =  FeCO3  +  Na2SO4 

Chlorids   Fe  +  2HC1  =  FeCl2  +  H2.        Fe2O3  +  6HC1  =  Fe2CL 

+  3H2O 

Hydrate   Fe2Cl6  +  ONH4OH  =  Fe2(OH)fl  +  6NH4C1 

lodid 2I2  +  Fe2  (filings  in  warm  water)  =  2FeI2 

Nitrate  Fe2(OH)0  +  6HNO,  =  6H2O  +  Fea(NO,)e 

Sulphates Fe  +  H2SO4   (dilute)   =  FeS04  +  H2.     Fe.O,  +  3H2- 

S04  =  Fe2(S04)3  +  3H20 
Sulphid Fe  +  S2  (fused  together)  =  FeS2 

Lead. 
Acetate PbO  +  2HC2H.,O2  =  Pb(C2H3O2)2  +  HaO 

32 


498  APPENDIX. 

Lead  (Concluded). 

Basic  Carbonate  .  .  .Dutch  method:  3Pb  +  02  (air)  +  2C(X  (manure  or 
tan-bark)  +  2HC2H302  (vapors)  —  Pb2(OH)2.- 
2C2H302  +  2C02  +  H20  +  O  +  Pb  = 
(PbC03),.Pb(HO)2  +  2HC2H302 
French  method:  3PbO  +  3Pb(C2H8O8)a  =  Pb30(C2- 
H302)4H-Pb3O,(CoH3O2)2.  These  and  2CO,  + 
H20  —  (PbC03)2Pb(HO)2  +  3Pb(C2H302)2 

lodid Pb(NO3)2  +  2KI  =  PbI2  +  2KNO3 

Monoxid    PbC03  (heated  to  low  redness)  =  PbO  -f  C02 

Nitrate PbO  +  2HN03  =  Pb(N03)2  +  H20 

Oleate  3PbO  +  3H2O  +  2C3H5(C18H3302)3  (olive-oil)  =  2C3- 

H5(HO)3  +  3Pb(C]8H3302)2 

Subacetate    PbO  +  Pb(C2H302)2  =  Pb2O(C2H3O2)2 

Lithium. 

Bromid LLC03  +  2HBr  =  2LiBr  +  C02  +  H2O 

Carbonate    Li4SiO4    (lepidolite)    +  H,S04  +  H,0  +  Ca(HO)2  — 

4LiOH,  etc. 
4LiOH  +  2  (NH4)  2C03  =  2Li2C03  +  4NH4OH 

Chlorid Li2CO3  +  2HC1  =  2LiCl  +  C02  +  H,O 

Citrate    3Li2C03  +  2H3Cv;H5O7  =  2Li3C6H5O7  +  3H2O  +  3CO2 

Salicylate LiaCO,  +  2HC7H5O3  =  2LiC7H503  +  H20  +  CO, 

Magnesium. 

Carbonate    5MgSO4    +    5Na2C03    +    6H2O    =    (MgCO,)4.Mg- 

(HO)2.5H2O  (heavy  or  official  carbonate)  + 
5Na2SO4  +  C02 

Citrate    3(MgC03)4.Mg(HO)2.3H2O  +  10H3C6H5O7  +  49ILO 

=  5Mg3(C6HB07)2.14H2O  +  12C02  (more  CO2  is 
produced  by  dropping  in  crystals  of  KHCO3 
just  before  corking  and  wiring). 

Hydrate  MgSO4  +  2NaHO  =  Mg (HO) 2  +  Na2SO4 

Oxid    (MgC03)4.Mg(HO)o.5H2O  (ignited)  =5MgO  (heavy, 

or  official)   +  6H20  +  4CO2 

Sulphate    MgC03  +  H2SO4  =  MgS04  +  CO2  +  H20 

Manganese. 

Sulphate    MnO2  +  H2S04  =  MnSO4  +  H20  +  O 

Mercury. 

Ammoniated HgCl2  +  2NH4HO  =  NH2HgCl  +  NH4C1  +  2H.,O 

Chlorids   Hg.,SO4  +  2NaCl  =  Hg2Cl2  +  Na2SO4 

HgSO4  +  2NaCl  (sublime)  =  HgCl2  +  Na2SO4 

Cyanid   HgO -f  2HCN  =  Hg(CN)2  +  H20 

lodids  Hg2(N03)2  +  2KI  =  Hg2I2  +  2KNO3 

HgCl2  +  2KI  =  HgI2  +  2KC1 

Nitrate  HgO  (red)  +  2HNO3  +  H20  =  Hg(N03)2  +  2H..O 

Oxid    HgCl2  +  2NaHO  =  HgO  (yellow)   +  2NaCl  +  H2O 

Subsulphate    3Hg  +  H2SO4  +  HN03  +  H20  =  Hg(HgO)2S04,  etc. 

Sulphate    Hg  +  2H2S04  =  HgS04  +  S02  +  2H,O 

Nitrogen. 

Ammonia (NH4)2SO4  +  Ca(HO)2==CaSO4  +  2NH3  +  2H.O 

Dioxid    3Cu  +  8HNO3  =  3Cu  (NOS)  2  +  N202  +  4H2O 

Monoxid    NH4NO;J  (heated)  =  N2O  +  2H2O 

Platinum. 

Chlorid  Pt  +  2C12  (aqua  regia)  =  PtCl4 

Potassium. 

Acetate K2C03  +  2HC2H,O2  =  2KC2H,O2  +  H.,0  +  CO2 

Arsenite  As203  +  2KHCO3  +  H20  =  2KH2As03  +  2CO2 


EQUATIONS.  499 

Potassium  (Concluded). 

Bicarbonate K2CO3  +  CO2  +  H2O  =  2KHCO3 

Broinid FeBr2  +  K2CO3  =  2KBr  +  FeCO3 

Chlorate OCa(HO)a  +  GCI,  =  5CaCl2  +  Ca(C103),  +  6H2O 

Ca(ClO,)2  +  2KC1  =  2KC1O3  +  CaCl, 

Chlorid  K2C03  +  2HC1  =  2KC1  +  H20  +  C02 

Chromate K,Cr,O7  +  K2CO3  =  2K2CrO4  +  CO, 


Cyanid    K4Fe(CN)6  +  K,C08  =  5KCN  +  KCNO  +  C02 

Dichromate   2K2CrO4  +  H2S04  =  K,Cr,0T  +  K2SO4  +  H,0 

Ferrocyanid     40  +  2N   (animal  scrap)   +  K2CO3  =  2KCN  +  SCO 

6KCN  +  FeS  =  K4Fe(CN)6  +  K2S 

Hydrate   K.CO,  +  Ca (HO) ,  =  2KHO  +  CaCO3 

Hypophosphite  .  . .  .Ca(H2P02)2  +  K,CO3  =  2KH2PO,  +  CaCO, 

lodid Fe2I6  +  3K,CO»  +  3H..O  =  6KI  +  3CO2  +  Fe2(HO)8 

6KOH  +  31.,  =  SKI  +  KIO,  +  3H2O 

Nitrate NaNO3  +  KC1  =  KN03  +  NaCl 

Permanganate    ....  3K2Mn04  +  2C02  =  K2Mn208  +  Mn02  +  2K2CO3 

Sulphate    2KN03  +  H2S04  =  2HN03  +  K2SO4 

Tartrate   of   K  and 

Na  2KHC4H400  +  Na2C03  =  2KNaC4H4O6  +  CO2  +  H20 

Silver. 

Broinid AgNO3  +  KBr  =  AgBr  +  KNO, 

lodid AgN03  +  KI  =  Agl  +  KN03 

Nitrate 3Ag  +  4HNO3  =  3AgN03  +  2H2O  +  NO 

Oxid    2AgNO,  +  2NaHO  =  Ag20  +  2NaNO3  +  H20 

Sodium. 

Acetate NaHCO3  +  HC,H302  =  NaC,H30,  +  CO2  +  H20 

Benzoate    HC7H502  +  NaHCO3  =  NaC7H5O2  +  CO2  +  H2O 

Bicarbonate Na2CO3  +  COa  +  H-.O  =  2NaHCO3 

Bisulphite   Na2CO3  +  2SO2  +  H,0  =  2NaHSO3  +  C02 

Bromid FeBr,  +  Na2C03  =  FeC03  +  2NaBr 

Carbonate    Leblanc  process :  NaCl  +  HnS04  =  NaHSO4  +  HC1 

NaHS04  +  NaCl  =  Na2S04  + 

HC1 

Na2S04  +  4C  =  Na2S  +  4CO 
Na2S  +  CaC03  =  Na2CO3  +  CaS 
Solvay's    ammonia-soda    process :     NaCl  +  NH3  + 
CO2  +  H20  =  NaHCO3  +  NH4C1.     2NaHC03 
(heated)  =  Na2CO3  +  CO2  +  H2O 

Hydrate  Na2C03  +  Ca(HO)2  =  2NaHO  +  CaC03 

Hypochlorite Ca(ClO)o  +  CaCl2  +  2Na2CO3  =  2NaC10  +  2NaCl 

+  2CaCO3 
Hypophosphite  . . .  .Na2C03  +  Ca(PH202)2=:2NaPH2O2  +  CaCO3 

lodid 6NaHO  +  3I2  =  5NaI  +  NalO3  +  3H.O 

Nitrite    NaN03  +  Pb  (heat  in  Fe  vessel)  =  NaNO2  +  PbO 

Phosphate   Na2CO3  +  H3PO4  (till  faintly  alkaline)  =  Na2HP04 

+  C02  +  H20 
Pyrophosphate  .  . .  .2Na2HPO4  (heated  to  250°)  =Na,PA  +  H2O 

Salicylate NaHO  +  HC7H503  =  NaC7H5O3  +  H20 

Silicate 4Si02  +  Na2CO3  -f  C  (fused  together)  =  Na2Si4O9 

+  C02  +  C 

Sulphite   2NaHS03  +  Na2CQ,  =  2Na2SO3  +  CO2  +  H20 

Sulphocarbolate  . . .  Na2CO3  +  2C6H3HSO3  =  2NaCcH4HS03  +  H2O  +  CO2 
Thiosulphate    ("Hy- 
posulphite")   ....  Na2SO3  +  S  (boiled  together)  =  Na,S2O3 


500  APPENDIX. 

Strontium. 

Bromid  SrCO3  +  2HBr  =  SrBr,  -f  CO,  +  H.O 

lodid SrC03  +  2HI  =  SrI2  +  CO,  +  H2O 

Lactate 2HC3H5O3  +  SrCO3  =  Sr(C3HBO8)2  +  H20  +  C02 

Nitrate  SrCO3  +  2HN03   (dilute)  =  Sr(NO3)2  +  H20  +  CO, 

Sulphur. 

Dioxid S2  +  202  (burn)  =  2SO2 

Trioxid  . 2SO2  +  02  (with  aid  of  red-hot  Pt  sponge)  =  2SO3 

Tin. 

Chlorids   Sn  +  2HC1   (hot)  =  SnCl2  +  H2 

Sn  +  2HgCl2  (distilled  together)  =  SnCl4  -f  Hg2 

Zinc. 

Acetate ZnO  +  2HC2H3O2=rZn(C2H3O2)2  +  H20 

Bromid   Zn  +  Br2  +  H2O    (warmed  gently)   =  ZnBra  +  H2O 

Carbonate    5(ZnSO4.7H2O)     +    5(Na2CO3.10H.,O)    =    2ZnCO3.- 

3Zn(HO),  (basic  carbonate)  +  5Na2S04  +  3C02 
+  82H20 

Chlorid  ZnO  +  2HC1  =  ZnCl,  -f  H20 

lodid Zn  +  I2  (heated  together)  —  ZnI2 

Oxid    2ZnC03.3Zn(HO)2   (basic  carbonate  heated  to  low 

redness)  =  5ZnO  +  2C02  +  3H20 

Phosphid    3Zn2    (powdered    and    heated)    +    P4    (vapor)    = 

2Zn3P2 

Sulphate    ZnO  +  H2S04  =  ZnS04  +  H20 

Valerianate ZnSO4  +  2NaCBH90,  =  Zn(C8H0O,),  _j_  Na2SO4 


ORES,  ROCKS,  AND  MINERALS. 

Aluminum:  Corundum  or  adamant  spar,  A12O3  (emery,  granular; 
ruby,  amethyst,  and  sapphire,  crystalline) ;  spinelle,  MgO  -f-  A12O3;  dia- 
spore,  A1202(HO)2;  bauxite,  A12O2(HO)4  +  Fe2O3;  gibbsite,  A12(HO)«; 
cryolite,  Al2F6.6NaF;  alunite,  H8KA13S,014;  turquoise,  H5A12P08;  sili- 
cated  rocks,  such  as  kaolin  or  porcelain  clay,  H4Al2Si;,09;  rotten-stone 
(with  organic  matter),  slate,  marl,  basalt,  granite  or  laminated  talc, 
hornblende,  emerald,  aluminum  garnet;  topaz,  Al2ALSiO4FHO;  and  feld- 
spar (silicates  of  Al  and  K,  or  Ca  and  Na)  as  orthoclase,  KAlSi3Os;  and 
albite,  NaAlSi8O8. 

Ammonium:    Mascagnite,   (NH4).,S04. 

Antimony:  Stibnite,  Sb2S3;  senarmonite  (octahedra)  and  valentin- 
ite  (rhombic  prisms)  of  Sb2O3. 

Arsenic:  White  arsenic,  As203;  orpiment,  As2S3;  realgar,  As;,S2; 
arsenical  iron,  FeAs2;  arsenical  pyrites  or  mispickel,  FeAs2FeS2. 

Barium:  Heavy  spar,  BaSO^;  witherite,  BaCO3;  barytocelestite^ 
(BaSrCa)(S04)3;  barytocalcite,  (BaCa)  (COB),;  psilomelane,  MnBaO., + 
Mn02. 

Beryllium:  Beryl,  3BeSi03,  Al2(Si03)3  (green  =  emerald;  bluish 
green  =  aquam arine );  phenacite,  Be2SiO4;  chrysoberyl,  BeO,  A12O3. 

Bismuth:    Bismuthite,  Bi2S3;   bismuth-ocher,  Bi2O3. 

Boron:  Borax,  Na2B407.10H2O;  boric  acid,  H3B03;  borocalcite, 
CaB4O7.4H2O;  boronatrocajcite,  Na2B407,  2CaB4O7.18H2O. 

Cadmium:    Greenockite,  CdS  chiefly. 

Calcium:  Carbonate,  CaCO3  (limestone,  marble,  chalk,  calcite,  ar- 
ragonite,  coral,  marl,  shells);  dolomite,  MgCO3,  CaCO3;  fluorspar,  CaF2; 
anhydrite,  CaSO4;  selenite  (crystalline)  and  alabaster  or  gypsum,  CaSO4.- 


ORES.  501 

2H20;  sombrerite,  Ca3(PO4)2;  apatite  (phosphorite),  Ca3(PO4)2,  CaCl2; 
osteolite,  Ca3(P04)2,  CaF2;  nearly  all  silicated  rocks. 

Cerium:    Cerite,  H3(Ce,  La,  Di)3(Ca,  Fe)Si3O12. 

Cesium:    Pollux  or  pollucite,  H2Cs4Al4Si9O27. 

Chromium:  Chromite  or  chrome-iron  ore,  FeO,  Cr.,O3;  crocoisite, 
PbCrO4. 

Cobalt:  Linneite,  Co3S4;  tin-white  cobalt,  CoAs2;  cobaltite  or 
cobalt-glance,  CoAs2,CoS2;  cobalt-bloom,  Co3(As04)2;  smaltite  or  speiss- 
cobalt,  (CoFeNi)As,;  erythrite,  Co3As2O8.8H2O. 

Copper:  Red  copper  ore  or  cuprite,  Cu2O;  black  oxid,  CuO;  copper 
glance  or  chalcocite,  Cu2S;  malachite,  CuCO3,Cu(HO)2;  azurite,  (CuCO3)2,- 
Cu(HO)2;  copper  pyrites  (bornite,  chalcopyrite),  Cu2FeS2  or  Cu2S.Fe2S3; 
chalcanthet,  CuSO4;  libethenite,  HCu2P05. 

Gold:    Electrum  (gold  mixed  with  more  than  36  per  cent,  of  silver). 

Iron:  Iron  pyrites  ("fool's  gold")  or  coal  brasses,  FeS2;  red 
hematite  or  specular  iron  ore,  Fe2O3;  magnetite  or  lodestone,  Fe:5O4; 
lintonite  or  brown  hematite,  Fe2(HO)6;  siderite  or  spathic  ore,  FeC03; 
wolframite,  FeMnWO4;  vivianite,  H10Fe3P2O10 ;  arsenopyrite  (sulpharsen- 
ite) ;  pyrrhotite,  FesSu. 

Lead:  Galena,  PbS;  cerussite,  PbC03;  anglesite,  PbSO4;  wulfenite, 
PbMo04;  pyromorphite,  Pb3(PO4)2;  crocoisite,  PbCrO4;  cotunite,  PbCl2. 

Lithium:  Petalite,  LiAlSi4O10;  spodumene,  LiAlSi2O6;  lepidolite, 
HKLiAl2Si3010F. 

Magnesium:  Magnesite,  MgCO3;  dolomite,  MgCO3,CaCO3;  carnallite, 
KCl.MgCl2.6H2O;  kieserite,  MgSO4.H2O;  spinel,  MgAl2O4;  silicates:  talc 
(soapstone),  H2Mg3Si4O12;  potstone,  asbestos  (earth-flax),  meerschaum 
(seprolite),  steatite,  rensellaerite,  serpentine,  and  enstatite. 

Manganese:  Pyrolusite,  Mn02;  psilomelane,  H4MnO8;  braunite, 
Mn2O3;  manganite,  Mn2O3H-H2O;  hausmannite,  Mn3O4;  manganese  spar 
or  rhodochrosite,  MnCO3;  manganese  blende,  MnS;  haverite,  MnS2;  wad 
or  bog  manganese  (impure  peroxid  in  clay). 

Mercury:  Cinnabar,  HgS;  horn  quicksilver,  Hg2Cl2  +  HgJ2;  nat- 
ural amalgam,  HgAg. 

Molybdenum:  Molybdenite,  MoS.>;  wulfenite,  PbMoO4;  trioxid, 
Mo03. 

Nickel:  Garnierite  or  genthite,  H2(NiMg)SiO  +  Ag;  magnetic  py- 
rites or  nickeliferous  pyrrhotite  (Fe,  Ni,  and  S) ;  millerite,  NiS;  nic- 
colite  or  copper  nickel,  NiAs;  bunsenite,  NiO. 

Potassium:  Niter.  KNO3;  carnallite,  MgCl2,KClj  kainite,  K2SO4,- 
MgSO4,MgC!2.5H20;  schoenite,  K1SO4,2MgSOi.6H2O;  sylvite,  KClj  sili- 
cates (potash-feldspar,  granite,  syenite,  gneiss,  micaceous  schist). 

Silicon:  Silica,  SiO2:  rock  crystal  or  quartz  (crystalline — tripoli, 
bath-brick,  sandstone,  amethyst,  carnelian),  tridimite  (crystalline),  chal- 
cedony (amorphous — agate,  jasper,  flint),  opal  and  geyserite  (hydrated 
oxids),  silicified  wood  and  kicselguhr  (diatomaceous  earth);  silicated 
rocks  (clays,  slates,  feldspars,  mica,  meerschaum,  serpentine,  porphyry, 
basalt,  asbestos,  granite,  gneiss,  syenite,  pumice,  tourmaline,  pyroxene, 
amphibole,  etc.). 

Silver:  Argentite  or  silver  glance,  Ag2S  (nearly  always  with 
galena);  horn  silver,  AgCl;  iodid  and  bromid  of  silver;  proustite, 
Ag3AsS3;  pyrargyrite  (with  Sb2S3) ;  tellurid  (with  Te). 

Sodium :  Crude  deposits  of  NaN03  in  dry  regions  of  South  America. 
Rock-salt,  NaCl;  Chili  saltpeter,  NaNO3;  albite,  NaAlSi308;  cryolite, 
Al2FB,6NaF;  thenardite,  Na2SO4;  mirabilite,  Na2SO4.10H20. 

Strontium:    Strontianite,  SrCO3;  celestine  or  celestite,  SrSO4. 


502  APPENDIX. 

Tin:  Cassitcrite  or  tin-stone,  Sn02  (vein-  or  mine-  tin  and  stream- 
tin)  ;  sulphid. 

Uranium:    Uranite  or  pitch-blende,  U308. 

Zinc:  Zinc-blende  or  sphalerite,  ZnS;  calamine,  H2Zn2Si05;  smith- 
sonite,  ZnC03;  zincite  or  red  oxid,  ZnO;  franklinite,  (FeMnZn)  (FeMn)2O4. 


POPULAR  AND  ALCHEMIC  NAMES. 

A.  C.  E.  Anesthetic  mixture  of  1  volume  of  absolute  alcohol,  2 
volumes  of  chloroform,  and  3  volumes  of  pure  ether. 

After-damp.    Carbon  dioxid  in  mines  following  fire-damp  explosions. 

Aich's  Metal.     Alloy  of  Fe  and  Zn  used  for  casting  cannon. 

Algaroth  Powder.    Antimony  oxychlorid,  SbOCl. 

Alkermes  Mineral.     Sulphureted  antimony,  Sb2S3. 

Alleluia.     Wood-sorrel,  Oxalis  acetosella. 

Alum  Lake.     Commercial  sulphate,  A12(SO4)318H20. 

Alum  Silver.  A  strong,  light  alloy  used  in  some  parts  of  chemic 
apparatus. 

Amidon.     Starch. 

Antichlor.  Sodium  thiosulphate,  or  "hyposulphite,"  used  in  re- 
moving excess  of  Cl  in  bleaching  operations. 

Antifebrin.     Trade  name  of  acetanilid. 

Antifriction  Metal.  Any  alloy  having  a  low  coefficient  of  friction; 
hence  used  for  bearing  surfaces;  Babbitt's  metal  is  an  example. 

Apple-oil.    Amyl  valerianate. 

Aqua  Fortis.     Crude  nitric  acid. 

Aqua  Regia.     Nitromuriatic  acid. 

Aqua  Reginse.     Nitrosulphuric  acid;  used  to  dissolve  silver. 

Aqua  Vitae.     Brandy. 

Aquila  Alba.    Old  name  for  calomel. 

Argentum  Vivum.     Mercury. 

Argols.     Crude  cream  of  tartar  from  wine-casks. 

Azote.     Nitrogen. 

Azotic  Acid.     Nitric  acid. 

Baldwin's  Phosphorus.  Calcium  nitrate:  heated  and  exposed  to 
sunshine,  is  luminous  in  the  dark. 

Balsam  of  Soap.     Soap  liniment. 

Barilla.    Ashes  of  sea-plants. 

Bengal  Fires.  Red:  Powdered  shellac,  1;  Sr(N03)2,  5;  powdered  Mg, 
25  parts.  Green:  Powdered  shellac,  1;  Ba(NO3)2,  5;  powdered  Mg,  25 
parts. 

Berlin  Red.     Colcothar,  or  ferric  oxid. 

Bitter  Salts.    Epsom  or  English  salts,  MgS04. 

Bittern.  Mother-liquor  remaining  after  evaporation  and  crystalliza- 
tion of  NaCl  from  sea-water. 

Black  Antimony.     Antimony  trisulphid,  Sb2S3. 

Black  Ash.     Impure  Na2C03  mixed  with  carbon. 

Black  Drop.     Guttse  nigrse;  vinegar  of  opium. 

Black  Flux.  A  mixture  of  C  and  K2C03  made  by  igniting  cream 
of  tartar  with  one-half  its  weight  of  niter. 

Black  Lead.     Plumbago,  graphite;  used  for  lead-pencils. 

Black  Wash.     A  mixture  of  calomel  and  lime-water. 

Blaud's  Pill.     Ferrous  carbonate  with  an  alkaline  sulphate. 

Bleaching  Powder.    A  mixture  of  calcium  chlorid  and  hypochlorite. 


GLOSSARY.  503 

Blende.     Various  native  sulphids. 

Blister  Copper.  Crude  copper  obtained  by  roasting  a  mixture  of 
Cu2O  and  Cu2S. 

Blondine.     Hydrogen  peroxid  for  bleaching  hair. 

Blue  Mass.    Mercurial  pill. 

Blue  Ointment.     Mercurial  ointment. 

Blue-stone,  or  Blue  Vitriol.     Cupric  sulphate,  Roman  vitriol. 

Bole.     Soft  clay  colored  red  by  ferric  oxid. 

Bone-ash,  or  Bone-black.    Impure  Ca3(P04)2,  from  charring  of  bones. 

Bone-phosphate.     Calcium  phosphate,  Ca3(PO4)2. 

Borax.    Sodium  tetraborate,  Na2B4O7. 

Brimstone.    Roll  sulphur. 

British  Gum.     Dextrin. 

Brunswick  Green.    Oxychlorid  of  copper. 

Burnett's  Disinfecting  Fluid.  Solution  of  zinc  chlorid  (205  to  230 
gr.  per  oz.). 

Butter  of  Antimony,  Bismuth,  or  Zinc.  The  chlorids  of  these 
metals. 

Butter  of  Paraffin.     Petrolatum. 

Calcimine.  A  wash  for  walls  and  ceilings,  made  of  whiting,  glue, 
and  water,  and  often  tinted. 

Calcined  Magnesia.    MgO  from  burning  of  MgCO3. 

Calomel.    Mercurous  or  mild  chlorid  of  mercury. 

Camphene.     Oil  of  turpentine. 

Camphoid.  A  mixture  of  1  part  of  pyroxylon  and  20  each  of  cam- 
phor and  absolute  alcohol. 

Canada  Pitch.  Hemlock-pitch  from  hemlock-spruce,  Abies  Cana- 
densis. 

Caput  Mortuum.    Impure  Fe2O3  left  after  igniting  FeS2  or  FeS04. 

Caramel.     Burnt  sugar. 

Carbolic  Acid.     Phenyl  hydrate,  or  phenol,  C6H5HO. 

Carborundum.  An  extremely  hard  polishing  substance  made  by 
fusing  together,  in  an  electric  furnace,  sand,  salt,  sawdust,  and  carbon. 

Chameleon  Mineral.     Potassium  permanganate  or  manganate. 

Chinosol.  A  soluble,  crystalline,  yellow  powder  of  the  quinolin 
group;  disinfectant  and  deodorant. 

Chloralum.    A  disinfectant  composed  of  a  solution  of  impure  A12C10. 

Chloric  Ether.    Alcoholic  solution  of  CHC13. 

Chloros.  A  disinfectant  liquid  containing  10  per  cent,  of  available 
Cl. 

Choke-damp.     CO,  in  mines. 

Chrome-green.     A  mixture  of  chrome-yellow  and  Prussian  blue,  or 

CrA- 

Chromeisen.    A  tough  alloy  of  Fe  and  Cr. 

Chrome-vermilion.     Lead  dichromate,  PbCr2O7« 

Chrome-yellow.     Lead  chromate,  PbCrO4. 

Citrine  Ointment.     Mercuric-nitrate  ointment. 

Clemens's  Solution.     Solution  of  arsenate  and  bromid  of  K. 

Colcothar.     Rouge,  crocus,  Fe2O3- 

Colophony.     Rosin,  common  resin. 

Common  Salt.     Sodium  chlorid,  NaCl. 

Condy's  Solution.  Potassium  permanganate,  32  gr.  in  1  pint  of 
water. 

Constant  White.     Barium  tungstate. 

Copperas.     Green  vitriol,  ferrous-sulphate  crystals,  FeS04.7Aq. 

Copperas  Blue.    Cupric  sulphate,  CuSO4.5H20. 


504  APPENDIX. 

Corrosive  Sublimate.    Mercuric  chlorid,  bichlorid  of  mercury,  HgCL. 

Court  Plaster.     Emplastrum  ichthyocollae. 

Crab-Orchard  Salts.  MgS04  plus  FeSO4,  which  obviates  nauseous 
taste  and  prevents  griping. 

Crab's  Eyes  or  Stones.    Prepared  chalk. 

Cream  of  Tartar.  Potassium  bitartrate,  KHCJ14O0.  Small  crystals 
float  on  surface  of  liquid  on  rapidly  cooling  a  hot  solution. 

Crocus  of  Antimony.     Antimony  vermilion  or  oxysulphid. 

Crystals  of  Venus.    Cupric  acetate,  Cu(C2H302)3.H20. 

Cubic  Niter.  NaNO3,  which  crystallizes  in  rhombohedra  closely 
resembling  cubes. 

Dermatol.  Bismuth  subgallate;  a  sulphur-yellow,  odorless,  insol- 
uble powder. 

Dialyzed  Iron.  Ferric  hydrate  held  in  solution  by  Fe2Cl6,  the  ex- 
cess of  which  has  been  removed  by  dialysis. 

Diana.    Alchemic  name  of  silver. 

Dobell's  Solution.  A  mixture  of  1 1/2  dr.  of  carbolic  acid,  4  dr.  each 
of  borax  and  baking-soda,  14  Y2  dr.  of  glycerin,  and  enough  water  to 
make  8  oz. 

Donovan's  Solution.  An  aqueous  solution  containing  1  per  cent, 
each  of  AsI3  and  HgI2. 

Dover's  Powder.  Compound  ipecac  powder:  1  part  each  of  ipecac 
and  opium  to  8  parts  of  sugar  of  milk. 

Dutch  Liquid.     Ethene  dichlorid,  C2H4C12. 

Dutch  White.  Impure  white  lead,  or  a  mixture  of  3  parts  BaS04 
to  1  part  of  white  lead. 

Earth-wax.     Ozokerite,  hard  paraffin,  fossil  wax. 
Eau  de  Javelle.    Solution  of  potassium  hypochlorite,  KC1O. 
Elixir  of  Vitriol.    Aromatic  sulphuric  acid. 

Emerald  Green.  Schweinfurth  green,  acetoarsenite  of  copper, 
SCuAsA  +  Cu(C2H3O2)2. 

Emery.     Pulverized  corundum. 

Epsom  Salts.     Magnesium  sulphate,  MgS04.7H20. 

Essence  of  Mirbane.     Nitrobenzol. 

Ethiops  Mineral.    Black  mercurous  sulphid,  Hg2S. 

Felwort.     Gentian. 

Ferrier's  Snuff.    Compound  bismuth  powder. 
Fire-damp.     Methane,  marsh-gas,  CH4. 
Flake  White.     Pure  carbonate  of  lead. 
Flowers  of  Antimony.     Antimonous  oxid,  Sb^. 
Flowers  of  Arsenic.     Arsenous  oxid,  As20.,. 
Flowers  of  Benzoin.     Benzoic  acid,  HC7H5O;,. 
Flowers  of  Bismuth.     Bismuth  oxid,  Bi20s. 
Flowers  of  Sulphur.     Sublimed  sulphur. 
Flowers  of  Zinc.     Zinc  oxid,  ZnO. 
Fly  Stone.    Cobalt  glance,  a  mixture  of  Co  and  As. 
Fool's  Gold.    Iron  pyrites,  FeS2. 

Fowler's  Solution.  A  1-per-cent.  aqueous  solution  of  potassium 
arsenite,  K3AsO3,  rendered  alkaline  with  K2C03. 

Freezine.    Formaldehyd  used  as  a  preservative  by  milkmen. 
French  Chalk.    Talc,  soapstone,  steatite,  magnesium  silicate  chiefly. 
Fusel  Oil.    Amyl  alcohol,  CBHnOH. 


GLOSSARY.  505 

Glass  of  Antimony.     Fused  antimony  trisulphid,  Sb2S3. 

Glass  of  Borax.     Borax-bead  obtained  by  fusion. 

Glauber's  Salts.     Sodium  sulphate,  Na2SO4.10H2O. 

Golden  Sulphur.     Antimony  pentasulphid,  Sb2S5. 

Goulard's   Extract   and   Cerate.     Contain   subacetate   of  lead,   Pb- 


Green  Precipitate.     Subacetate   of  copper,  true  verdigris. 
Green  Vitriol.     Copperas,  tutia,  FeSO4.7H20. 

Guignet's  Green.  Chromic  hydrate  obtained  by  heating  a  mixture 
of  K2CraO7  and  boric  acid,  and  extracting  with  water. 

Hamburg  White.  Mixture  of  1  part  of  white  lead  and  2  parts  of 
BaSO4. 

Hard  Salt.    Powdered  alum. 

Hartshorn.     Ammonia,  NH3. 

Heavy  Carbureted  Hydrogen.     Ethene  or  olefiant  gas,  C2H4. 

Heavy  Earth.     Baryta,  BaO. 

Heberden's  Ink.     Mistura  ferri  aromatica. 

Hiera  Picra.     Aloes-and-canella  powder,  "hickery  pickery." 

Hive-syrup.    Compound  syrup  of  squill. 

Hoffmann's  Anodyne.  Compound  spirit  of  ether:  1  pint  each  of 
ether  and  alcohol,  6  fluidrams  of  ethereal  oil. 

Holy-wood.     Guaiacum,  lignum  vitse,  pock-wood. 

Honey-dew.  A  viscid  mixture  of  cane-sugar,  dextrin,  and  invert- 
sugar,  exuded  from  aphides  on  leaves. 

Huxham's  Tincture.     Compound  tincture  of  cinchona. 

Ice-vinegar.     Glacial  acetic  acid. 

Ignis  Fatuus.     Will-o'-the-wisp;    spontaneous  combustion  of  phos- 
phine,  H3P,  generated  in  marshy  places. 
Indian  Salt.     White  sugar. 

Iron  Pyrites.     Native  sulphid  of  iron,  "fool's  gold,'*  FeS2. 
Italian  Juice.     Licorice. 
Ivory  Black.     Animal  charcoal  or  bone-black. 

James's  Powder.  Antimonial  powder:  1/3  oxid  of  antimony,  2/3 
calcium  phosphate. 

Japan  Black.  A  varnish  of  asphalt,  umber,  turpentine,  and  lin- 
seed-oil. 

Jesuit's  Powder.     Powdered  cinchona-bark. 

Jewelers'  Gold.    Alloys  of  gold  and  silver. 

Kalk.     Lime,  CaO. 

Kelp.     Sea-weed  ashes  used  as  a  source  of  I  and  Na2CO3. 

Kermes  Mineral.     Oxysulphid  of  antimony. 

King's  Yellow.     Orpiment,  As2S3. 

Labarraque's  Solution.    Solution  of  sodium  hypochlorite,  NaClO. 

Lady  Webster  Pill.    Aloes  pill. 

Lana  Philosophica.     Zinc  oxid,  ZnO. 

Lapis  Infernalis.     Lunar  caustic. 

Lapis  Lazuli.    Natural  ultramarine,  a  beautiful  dark-blue  pigment. 

Laughing-gas.     Nitrous  oxid,  N20. 

Lead-water.    Diluted  Goulard's  extract,  containing  lead  subacetate. 

Lemon-chrome.     Chrome-yellow,  PbCrO4. 

Lightning  Powder.     Lycopodium,  "vegetable  sulphur." 


506  APPENDIX. 

Lime.    Calcium  oxid,  CaO. 

Lime-water.     Aqueous  solution  of  Ca(HO)2 — about  0.15  per  cent. 

Liquid  Smoke.     Pyroligneous  acid. 

Litharge.    Massicot,  lead  oxid,  PbO. 

Liver  of  Sulphur.  Hepar  sulphuris;  sulphureted  potassium,  K2S, 
a  liver-brown  solid. 

Lodestone.     Native  magnetic  oxid  of  iron,  Fe304. 

Lokas,  or  Chinese  Green.  A  pigment  obtained  by  evaporating  to 
dryness  a  mixture  of  lime  and  the  juice  of  buckthorn-berries. 

London  Paste.  Equal  parts  of  quicklime  and  caustic  soda,  made 
into  a  paste  with  water;  a  depilatory. 

London  Purple.     Arsenical  residues  from  anilin-dye  manufactories. 

Lugol's  Solution.  lodin  (5)  held  in  solution  by  KI  (10)  in  dis- 
tilled water  (85). 

Luna.    Alchemic  name  for  silver/ 

Lunar  Caustic.  Stick  silver  nitrate,  AgN03,  toughened  with  5-per- 
cent. IiN03. 

Magendie's  Solution.  Morphin  sulphate,  16  gr.  to  the  ounce  of 
water. 

Magican.     Galls. 

Magnesia  Alba.    Magnesium  carbonate. 

Matte.  Impure  metal  (especially  Cu)  containing  S.  Called  also 
"regulus,  or  white  metal." 

Microcosmic  Salt.     Sodium  ammonium  phosphate,  NaNH4HP04. 

Milk  of  Asafetida.    The  white,  aqueous  emulsion  of  this  gum. 

Milk  of  Lime.     Whitewash. 

Milk  of  Magnesia.    Mg(HO)2  suspended  in  water,  1  part  to  15. 

Milk  of  Sulphur.  Lac  sulphuris,  or  precipitated  sulphur,  mixed 
with  water. 

Mineral  Blue.     Prussian  blue,  Fe4(FeCy6)3. 

Mineral  Pitch.     Asphalt. 

Mineral  Yellow.     Lead  oxychlorid. 

Monsel's  Solution.     Liquor  ferri  subsulphatis,  Fe40(S04)5. 

Mosaic  Gold.  Brass  or  stannic  sulphid,  a  golden-yellow  powder 
used  for  bronzing. 

Mountain-blue.     Azurite,  native  basic  cupric  carbonate. 

Mountain-green.    Malachite,  native  basic  cupric  carbonate. 

Muriatic  Acid.     Hydrochloric  acid,  HC1. 

Music  Metal.    Alloy  of  Sn  and  Sb. 

Mystery  Gold.  Alloy  of  1  part  Pt  and  2  parts  Cu  with  a  little 
silver.  It  resists  action  of  strong  nitric  acid. 

Naples  Yellow.    A  basic  lead  antimonate  used  in  oil-painting. 
Natron.    Native  sodium  carbonate,  Na2CO3. 
Neutral  Mixture.     Solution  of  potassium  citrate,  K3C0H507. 
Niter.     Saltpeter,  KN03. 

Obsidian.     Volcanic  glass;  trachyte  or  rhyolite. 

Ocher.    Native  mixture  of  clay  and  ferric  oxid,  used  as  a  paint. 

Oil  of  Vitriol.     Sulphuric  acid,  H2S04. 

Oil  of  Wine.    Ethyl  sulphate,  (C2H5)2S04.   ' 

Olefiant  Gas.  Ethene,  C2H4;  so  called  because  it  makes  an  oily 
liquid  with  Cl. 

Oleum  Calcis.  The  thick,  oily  liquid  resulting  from  deliquescence 
of  CaCl2  exposed  to  the  air. 


GLOSSARY.  507 

Oxidized  Silver.  Coating  of  thin  layer  of  sulphid,  obtained  by 
heating  together  Ag  and  solution  of  K2S. 

Ozonized  Ether.     Solution  of  H^O2  in  ether. 
Ozonized  Water.     Aqueous  solution  of  H2O2. 

Packfong.     German  silver,  or  brass  whitened  by  nickel. 

Palsy  Drops.    Compound  tincture  of  lavender. 

Paris  Black.     Finely  ground  animal  charcoal. 

Paris  Green.     Impure  Schweinfurth,  or  mitis,  green,  Cu(C2H302)2>- 

3CuAs2O4. 

Paris  Yellow.     Lead  chromate,  PbCr04. 

Pearl  Ointment.     Zinc-oxid  ointment. 

Pearl  Powder  or  White.    Subnitrate  or  subchlorid  of  Bi,  or  ZnO. 

Pearl-ash.  Crude  potassium  carbonate,  K2CO3,  calcined  in  a  furnace 
till  white. 

Pearson's  Salt.     Sodium  arsenate,  Na3As04. 

Pectoral  Powder.    Pulvis  glycyrrhizae  compositus. 

Permanent  White.  Barium  sulphate  or  carbonate — not  darkened 
by  H2S. 

Phlogiston.     Hydrogen. 

Phosgene-gas.     Carbonyl  chlorid,  COC12. 

Pink  Salt.     Stannic  chlorid  with  ammonium  chlorid. 

Pink  Saucers.     Carthamin,  a  red  dye  in  safflower. 

Plaster  of  Paris.     Calcined  gypsum  or  calcium  sulphate. 

Plate  Pewter.  An  alloy  of  Sb  and  Sn  used  for  faucets  and  domestic 
utensils. 

Platinum  Black  and  Sponge.    Finely  divided  Pt. 

Plumbago.     Black  lead,  graphite,  a  form  of  native  carbon. 

Plummer's  Pill.    Compound  antimony  pill,  Sb2S3,  Sb203,  and  calomel. 

Poison-nut.     Nux  vomica. 

Pompholix.     Zinc  oxid,  ZnO. 

Potash.     Impure  potassium  carbonate,  K2CO3. 

Potassa.    Potassium  oxid  or  hydrate. 

Potato-oil.    Crude  amyl  alcohol. 

Pot-metal.     An  alloy  of  Cu  and  Pb. 

Pounce.    Powdered  gum  juniper. 

Preservaline  or  Rex  Magnus.    A  mixture  of  borax  and  boric  acid. 

Prince's  Powder.     Red  oxid  of  mercury,  HgO. 

Printers'  Ink.  Thoroughly  boiled  linseed-oil  varnish,  containing 
lamp-black  or  other  color  and  a  little  soap. 

Proof-spirit.  The  old  name  applied  to  dilute  alcohol  49  1/4  per  cent., 
by  weight  (57  per  cent.,  by  volume)  ;  so  called  because  this  is  the  lowest 
alcoholic  limit  with  which  gunpowder  will  take  fire. 

Prussian  Blue.     Ferric  ferrocyanid,  Fe4(FeCy6)3. 

Prussic  Acid.    Hydrocyanic  acid,  HCN. 

Puce  Oxid  of  Lead.     Brown  or  peroxid  of  lead,  Pb02. 

Punk.  Amidou,  touch-wood;  made  by  steeping  a  fungus  in  salt- 
peter solution,  and  then  drying  thoroughly. 

Purple  of  Cassius.  Pigment  made  by  mixing  solutions  of  AuCl3 
and  SnCL;  probably  Au2OSn3O3. 

Putty.    Mixture  of  whiting  and  linseed-oil. 

Putty  Powder.     Stannic  oxid,  Sn02. 

Queen's  Metal.     An  alloy  of  Sb,  Sn,  etc.,  used  in  jewelry. 
Quevenne's  Iron.     Iron  reduced  by  hydrogen. 
Quicklime.     Caustic  lime,  CaO. 
Quicksilver.    Metallic  mercury. 


508  APPENDIX. 

Ratsbane.    Nux  vomica,  phosphorus,  arsenic. 

Red  Blister.     Uuguentum  hydrargyri  iodidi  rubri. 

Red  Cerate.     Calamine  ointment. 

Red  Fire.  Sr(NO3)2,  50  parts;  KC1O3,  25  parts;  powdered  shellac 
or  sugar,  25  parts;  mixed  without  friction  through  a  sieve. 

Red  Lead.    Minium,  plumboso-plumbic  oxid,  (PbO)2Pb02. 

Red  Oil.  Oleic  acid  as  a  by-product  in  the  manufacture  of  stearic 
acid  candles. 

Red  Precipitate.     Red  mercuric  oxid,  HgO. 

Red  Pmssiate  of  Potash.     Potassium  ferricyanid,  K0Fe2Cy12. 

Red  Tartar.     Argols,  impure  cream  of  tartar. 

Regulus  of  Antimony.     Metallic  antimony. 

Regulus  of  Arsenic.  Metallic  As  obtained  by  reduction  of  As203 
with  powdered  C. 

Rex  Metallorum.     Gold. 

Rinman's  Green.  A  pigment  made  by  pptg.  a  mixture  of  zinc  and 
cobalt  sulphates  with  Na2CO3,  and  igniting  ppt.  after  washing. 

Rochelle  Salt.    Potassium  and  sodium  tartrate,  KNaC4H4O0. 

Rose  Pink.  Whiting  colored  writh  a  decoction  of  Brazil  wood  and 
alum. 

Rouge.  Mineral:  finely  powdered  ferric  oxid.  Animal:  carmin 
and  chalk.  Vegetable:  carthamin  and  chalk. 

Rust.    Ferric  oxid  and  hydrate. 

Safety  Oil.     Petroleum  naphtha. 

Sal  Alemboth.  Salt  of  wisdom;  double  chlorid  of  mercury  and 
ammonium,  NH2HgCL 

Sal  Ammoniac.     Ammonium  chlorid,  NH4C1. 

Sal  Diureticus.     Potassium  acetate,  KC2H302. 

Sal  Enixum.    Potassium  bisulphate,  KHSO4. 

Sal  Marinum  or  Fossile.     Sodium  chlorid. 

Sal  Mirabile.     Sodium  sulphate,  Na2SO4. 

Sal  Perlatum.     Sodium  phosphate. 

Sal  Polychrest.     Sal  de  duobus,  potassium  sulphate,  K2SO4. 

Sal  Prunelle.     Fused  saltpeter,  KNO3. 

Sal  Soda.     Impure  Na2CO3,  containing  hydrate. 

Sal  Vegetabile.    Potassium  tartrate. 

Sal  Volatile.    Ammonium  carbonate  or  aromatic  spirit  of  ammonia. 

Saleratus.     Potassium  bicarbonate,  KHC03. 

Salt  of  Lemon  or  Sorrel.     Potassium  binoxalate,  KHC2O4. 

Sa.lt  of  Mars  or  Steel.    Sulphate  of  iron. 

Salt  of  Saturn.     Lead  acetate,  Pb(C2H302)2. 

Salt  of  Tartar.  Pure  potassium  carbonate,  K2C03;  so  called  be- 
cause sometimes  made  by  burning  cream  of  tartar  and  lixiviating  residue. 

Saltpeter.    Potassium  nitrate,  KNO3. 

Saprol.  A  dark-brown,  oily  cresol  much  used  in  Germany  as  a  dis- 
infectant. 

Scheele's,  or  Swedish,  Green.       Cupric  arsenite,  CuHAsO3. 

Schlippe's  Salt.  Sodium  sulphantimonate,  NasSbS4,  used  in  pho- 
tography. 

Schweinfurth,  or  Vienna,  Green.     Same  as  Paris  green. 

Sedative  Salt.     Boric  acid,  H3BO3. 

Seidlitz  Powder.  Compound  effervescing  powder:  Tartaric  acid 
(35  gr.)  in  white  paper;  Rochelle  salt  (120  gr.)  and  sodium  bicarbonate 
(40  gr.)  in  blue  paper. 

Seignette  Salt.     Same  as  Rochelle  salt. 


GLOSSARY.  509 

Sienna.     Native  oxid  of  iron  used  as  a  red  pigment. 

Smalt.     Powdered  glass  colored  blue  with  oxid  of  cobalt. 

Smelling   Salts.      Sal    volatile,  chiefly   ammonium   carbonate. 

Soda  Saltpeter.     Sodium  nitrate,  NaNO3. 

Soda-water.     Water  charged  artificially  with  C02  under  pressure. 

Soldiers',  or  Troopers',  Ointment.     Unguentum  hydrargyri  mitis. 

Soluble,  or  Water,  Glass.     Sodium  silicate,  Na2Si4OB. 

Soluble  Starch.     Amylodextrin. 

Sory,  or  Shoe-makers',  Black.     Sulphate  of  iron. 

Speculum  Metal.     An  alloy  of  Cu  and  Sn. 

Speiss.     Impure  fused  nickel  arsenid. 

Spelter.    Commercial  zinc  or  an  alloy  of  equal  parts  Zn  and  Cu. 

Spiegeieisen.     Ferromanganese. 

Spirit  of  Hartshorn.  Solution  of  NH3  in  alcohol.  Ammonia  was 
formerly  made  from  horns  and  hides. 

Spirit  of  Mindererns.  Solution  of  ammonium  acetate,  made  by 
neutralizing  dilute  acetic  acid  with  ammonium  carbonate. 

Spirit  of  Niter.     Nitric  acid,  HNO3. 

Spirit  of  Salt.     Hydrochloric  or  marine  acid,  HC1. 

Spirit  of  Vinegar.     Dilute  acetic  acid,  HC2H3O2. 

Spirit  of  Wine.  Rectified  ethyl  alcohol,  C2H5OH,  of  84-per-cent. 
strength. 

Steel  Drops.     Tincture  of  chlorid  of  iron. 

Steinbuhl  Yellow.     Barium  chromate,  BaCr04. 

Strike.     Liquor  ammonise. 

Stucco.     Calcium  sulphate,  CaSO4. 

Sugar  of  Lead.    Lead  acetate,  Pb(C2H302)2. 

Sulphuric  Ether.     Ethylic  ether,  (Q,H5)2O. 

Sweet  Precipitate.     Mercuric  chlorid,  HgCl2. 

Sweet  Principle  of  Fats.     Glycerin  was  formerly  so  called. 

Sweet  Spirit  of  Niter.     Spiritus  setheris  nitrosi,  C2H5N02. 

Talmi  Gold.     Alloy  of  Cu  and  Al. 

Tar  Balls.     Coal-tar  camphor,  naphthalene. 

Tar  Spirit.     Benzol,  C6HG. 

Tartar  Emetic.     Potassium  antimonyl  tartrate,  KSbOC4H4O6. 

Terra  Alba.  Argilla,  kaolin  or  bolus  alba,  a  white  argillaceous 
earth. 

Thenard's  Blue.     A  compound  of  the  oxids  of  Al  and  Co. 

Thenard's  Green.     Phosphate  of  cobalt. 

Tin  Salt.     Tin-  ash  or  crystals:    stannous  chlorid,  SnCl2.2H2O. 

Tincal.     Native  borax,  Na2B4O7.10H20. 

Tombac.    Copper  alloyed  with  As  and  used  for  imitation  jewelry. 

Tournesol.     Litmus,  laque  blue. 

Tripoli.  Diatomaceous  earth,  chiefly  fine  silica,  used  as  a  polishing 
powder. 

Trona.     Native  sodium  carbonate,  Na2C03. 

Tully's  Powder.  Compound  morphin  powder:  1  part  of  morphin 
to  20  each  of  camphor,  licorice,  and  calcium  carbonate. 

TurnbulFs  Blue.    Ferrous  ferricyanid,  Fe8(Fe2Cy,2). 

Turner's  Cerate.     Calamine  ointment. 

Turner's  Yellow.     Lead  oxychlorid. 

Turpeth  Mineral.  Queen's  yellow,  subsulphate  of  mercury,  HgS04.- 
2HgO. 

Tutenag.     Zinc. 

Tutty.     Impure  zinc  oxid,  ZnO. 


510  APPENDIX. 

Ultramarine,  or  Washing,  Blue.  Lapis  lazuli,  a  blue  pigment  com- 
posed of  sodium  sulphid  and  aluminum  sodium  silicate. 

Umber.  Sienna  or  chestnut  brown,  native  aluminum  silicate  with 
oxids  of  iron  and  manganese,  used  as  brown  paint;  darkened  in  tint  by 
burning. 

Valangin's  Solution.     Solution  of  As203  with  dilute  HC1. 
Vallet's  Mass.     Ferrous  carbonate  in  pill  mass. 
Varec.     Kelp,  or  ash  of  sea-weeds. 

Venetian  Red.    An  ocher,  the  color  of  which  is  due  to  ferric  oxid. 
Venus.     Alchemic  name  for  copper. 
Verditer  Green.     Basic  copper  carbonate. 
Vermilion.     Artificial   mercuric  sulphid,  HgS. 

Vinegar  of  Lead.  Liquor  plumbi  subacetatis,  a  solution  of  PbO  in 
Pb(C2H3O2)2  solution. 

White  Acid.    A  mixture  of  HF  and  NH4F  used  for  etching  glass. 
White  Arsenic.     Arsenous  oxid,  As2O3. 
White  Lead.     Basic  lead  carbonate,  (PbC03)2Pb(HO),. 
White  Metals.    Alloys  of  Ni  with  Cu  and  Zn:    albata,  British  plate, 
electrum,  packfong,  tutenag,  white  copper,  etc. 

White  Precipitate.    Ammoniated  mercury,  NH2HgCl. 
White  Vitriol.    Zinc  sulphate,  ZnS04. 
Whiting.     Prepared  chalk,  CaC03,  or  white  clay. 
Wood-spirit,  or  Naphtha.    Methyl  alcohol,  CH3OH. 
Wood-vinegar.     Pyroligneous,  or  impure  acetic,  acid. 

Yellow  Ointment.     tTnguentum  hydrargyri  nitratis. 
Yellow  Prussiate  of  Potash.     Potassium  ferrocyanid,  I^FeCy,.,. 
Yellow  W^ash.    Mercuric  oxid,  HgO,  made  by  adding  HgCl2  to  lime- 
water. 

Zaffre.     Impure  cobaltous  oxid  from  roasting  sand  and  ore. 
Zinc,  or  Chinese,  White.    Zinc  oxid,  used  as  paint. 


INDEX. 


Absinthin,  230 
Absorption,  398 

of  gases,  18 
Acetals,  212 
Acetamid,  238 
Acetanilid,  239,  326,  356 
Acetates,  177 
Acetic  acid,  213,  368,  419 
Aceton,  212,  369,  376,  454 
Acetonuria,  454 
Acetylene,  196,  326 
Acid,  finding,  263 
Acidity,  82 
Acids,  80,  81,  144 
Aconite  poisoning,  355 
Aconitin,  244 
Actinism,  37,  102 

Action    of   air,   light,    and    atmos- 
pheric heat,  303 

of  air  on  metais,  100 

of  metals  on  water,  100 
Acute  poisoning,  336 
Adenin,  370 
Adhesion,  5 
Adipocere,  215,  371 
Adonidin,  230 
Adrenalin,  390 

Adulterants  and  sophisticants,  319 
Agglutination,  415 
Air,  125,  307 
Albuminates,  247,  250 
Albuminoid  ammonia,  317 
Albuminoids,  249 
Albuminometer,  449 
Albumins,  246,  247 
Albuminuria,  441 
Albumoses,  247,  408 
Albumosuria,  449 
Alcohol,  326,  410,  419 

poisoning,  352,  360 
Alcohols,  204 
Aldehyds,  210 
Alizarin,  233 

Alkaline  phosphates,  434,  465 
Alkaloids,  241,  245,  277,  278,  290, 

291 
Alkaptonuria,  455 


Alkyl  salts,  203 

Allantoin,  444 

Allotropic  elements,  59,  73,  99 

Alloxan,  369 

Alloxuric  bodies,  369,  441 

Alloys,  107 

Allyl  sulphid,  237 

Aloins,  234 

Alum  poisoning,  347 

Aluminates,  173 

Amalgam  alloys,  analysis,  286 

Amalgamation,  48 

Amido-acids,  239,  369 

Amido-phenols,  237 

Amids,  238 

Amins,  238 

Ammonia,  152,  315,  444 

Ammoniacal  fermentation  of  urine, 

430 
Ammonium,  95 

compounds,  102 

microchemic  test,  281 
Ampere,  49 
Amygdalin,  230 
Amyl  nitrite,  210 
Amyloid  corpuscles,  474 

substance,  248 
Amylopsin,  252,  381 
Anabolism,  400 
Anhydrids,  138 
Anilids,  239 
Anilin,  239 
Animal  electricity,  52 

foods,  407 

functions,  396 

heat,  400 

irritants,  349 
Anions,  61,  83 
Annatto,  test,  321 
Anode,  46 
Anthracene,  199 
Anticytotoxins,  415 
Antidotes,  342 
Antimonates,  172 
Antimony  poisoning,  346,  359 
Antipyrin,  240 
Antiseptics,  326 

(511) 


512 


INDEX. 


Antitoxins,  245,  413 

Anuria,  431 

Apomorphin,  243 

Aqua,  29 

Aqueous  vapor,  308 

Arbutin,  231 

Aristol,  204 

Aromatic  series,  198 

Arrow-poison,  356 

Arsenates,  171 

Arsenic  and  arsenous  acids,  151 

poisoning,  345,  358 

tests,  279,  281 
Arsenites,  171 
Artesian  wells,  12 
Articular  diseases,  481 
Asbestos,  176 
Ascitic  fluid,  395 
Ash  of  milk,  422 
Aspidospermin,  245 
Assays,  pharmaceutic,  283 
Atmosphere,  17 
Atomic  heat,  25 

weights,  73 
Atomicity,  73 
Atoms,  4,  72 
Atropin,  243,  282 
Attraction,  4 
Audiphone,  65 
Autointoxication,  411 
Autotoxemia,  411 
Avogadro's  law,  16 
Azo  compounds,  240 

Bacteria  in  milk,  320 
Bacteriolysins,  415 
Bacteriuria,  475 
Balloons,  18 
Balsams,  198 
Baptism,  231 
Barium  poisoning,  347 

test,  282 
Barometer,  17 
Bases,  81 
Basic  oxids,  133 
Basicity,  81 
Battery,  46 

-fluids,  47 
Beer,  206,  324 
Bee-stings,  364 
Benzene,  198 
Benzin,  193 
Benzoates,  180 
Benzoic  acid,  217,  326 
Berberin,  244 
Beverages,  410 
Bicarbonates,  165 


Bile,  381,  384 

-pigments,  384,  455 

-salts,  444 
Bilicyanin,  371 
Biliousness,  411 
Bilirubin,  371,  384 
Biliverdin,  371,  384 
Bilixanthin,  371 
Bitter  principles,  234 
Bixin,  233 

Bleaching  powder  poisoning,  347 
Blood,  375 

in  urine,  457 
Blow-pipe,  270 
Body-fat,  368 
Boiling-point,  22,  24 
Bones,  371 
Borates,  170 
Borax  bead  tests,  273 

in  milk,  320 

Boric  acid,  149,  320,  327 
Boroglycerin,  207 
Boron,  128 

Bottger's  test  for  sugar,  452 
Botulismus,  349 
Brain,  374 
Brasilin,  233 
Bread,  321,  408,  409 
Bright's     disease,     differentiation, 

477 

Bromates,  158 
Bromelin,  252 
Bromids,  157 
Bromin,  118,  327 
Bromism,  362 
Bromoform,  204 
Brucin,  244,  3.56 
Bryonin,  231 
Bunsen  flame,  270 
Butter,  221,  320,  387 
Butyric  acid,  215,  369,  419 

Cachexias,  412 

Cacodyl,  238 

Caffein,  370 

Cake,  321 

Calabar  bean,  356 

Calcium  carbonate  crystals,  464 

oxalate,  444,  463 

phosphate  crystals,  463 

sulphate  crystals,  464 

test,  282 

Calculi  of  urinary  tract,  483 
Calorie,  31,  405 
Calorimeter,  31,  401 
Camera  lucida,  35 

obscura,  36 


INDEX. 


513 


Camphor,  197,  353 

Cane-sugar,  227 

Caimabis  Indica  poisoning,  352 

Canned  goods,  321 

Cantharidin,  234 

Cantharis.  349 

Caoutchouc,  197 

Capillary  attraction,  10 

Carbainic  acid,  239 

C'arbamid,  238 

Carbazotic  acid,  236 

Carbids,  1G8 

Carbohydrates,  224 

Carbolates,  181 

Carbolic  acid,  235,  327,  345 

Carbon,  129 

compounds,  189 

dioxid  poisoning,  353 

monoxid  hemoglobin,  379 
poisoning,  353 

salts,  165 
Carbonates,  165,  367 

in  urine,  436 
Carbonation,  305 
Carbonic  acid,  149 
Carbylamins,  241 
Cardiac  failure,  19 
Carminic  acid,  232 
Cartilage,  375 
Caseinogen,  248 
Caseins,  247,  387 
Casts,  465 
Catabolism,  400 
Cataphoresis,  51 
Cathartic  acid,  231 
Cathode,  46 
Cations,  61,  83 
Caustic  alkalies,  344 
Celluloid,  226 
Cellulose,  225 
Cement  of  teetn,  372 
Cements,  175 
Centrifuge,  425,  459 
Cephalin,  245 
Cerebrin,  231,  368 
Cerebro-spinal  fluid,  390 
Cerumen,  386 
Charcoal,  130 
Charles's  law,  16 
Cheese,  321,  407 
Chemism,  5 
Chemistry,  1 
Chicory,  323 - 
Chinolin,  240 
Chitins,  231,  249 
Chloral,  211,  328,  352,  369 
Chloralamid,  238 


Chlorates,  156 
Chlorids,  154,  314,  344,  367 
Chlorin,  116,  328 
Chloroform,  203,  328,  357 
Chlorophyl,  232 
Chocolate,  323 
Cholalic  acid,  371 
Cholemia,  377 
Cholesterin,  371,  464 
Cholin,  370 
Choluria,  427,  455 
Chondrigen,  375 
Chondrin,  249 
Chromates,  172 
Chromatic  aberration,  38 
Chromium  poisoning,  363 
Chromoproteids,  248 
Chronic  poisoning,  357 
Chyle,  389 

Cnyluria,  428,  429,  456,  474 
Chymosin,  253 
Cimicifuga,  234 
Cinchona  group,  243 
Cinchonidin,  243 
Cinchonin,  243 
Cinnamic  acid,  217 
Citrates,  178 
Citric  acid,  217,  328 
Clays,  175 
Cleavage,  60 
Clotting  of  blood,  377 
Coal,  129 

-gas,  194 

poisoning,  353 

-tar  antipyretics,  356 

dye-colors,  233 
Cobalt  salts,  102 
Cocain,  244,  355,  361 
Cocculus  Indicus,  357 
Cochineal,  232 
Cocoa,  323,  411 
Codein,  243 
Coffee,  323,  362,  410 
Cohesion,  5 
Coke,  130 

Colchicum  poisoning,  348 
Collagen,  249,  371,  374,  375,  408 
Collodion,  226 
Colloids,  11 
Colocynthin,  231 
Color,  36,  37 

-changes,  304 

of  metals,  97 

of  urine,  426 

of  water,  314 

Coloring  matters  of  urine,  445 
vegetable,  232 


514 


INDEX. 


Colostrum,  388 
Combination  of  metals,  90 
Combustion,  299 
Compound  ammonias,  238 

solvents    in    aqueous    solutions, 

297 

Compressibility,  6 
Condensers,  43 
Condiments,  324,  409 
Conduction,  20,  44 
Confectionery,  323 
Coniferin,  231 
Coniin,  242 

Conium  poisoning,  355 
Conjugate  sulphates,  436 
Connective  tissue,  374 

in  urine,  474 
Consistence  of  urine,  429 
Constitutional  diseases,  481 
Contamination  of  water,  318 
Convallamarin,  231 
Convection,  20 
Convolvulin,  231 
Convulsants,  356 
Cooking,  409 
Copper  poisoning,  347,  359 

sulphate,  329 

test,  281 

volumetric  estimation,  279 
Corrosion  of  metals,  103 
Corrosive  sublimate,  282,  344 
Corrosives,  343 
Cotoin,  231,  234 
Coulomb,  50 
Cream,  422 
Creasote,  235,  329 
Creatin,  369,  409,  443 
Creolin,  329 
Cresol,  235 
Crystallin,  247 
Crystallization,  10 
Crystallography,  58 
Crystalloids,  11 
Crystals  in  urine,  460,  461 
Cubebin,  234 

Cupric  and  cuprous  salts,  102 
Curare,  356 
Curcumin,  232 
Cyanates,  182 

Cyanid  of  zinc  and  mercury,  329 
Cyanids,  182,  241,  354 
Cyanogen  poisoning,  363 
Cyano-salts,  182 
Cyanosis,  404 
Cylindroids,  466 
Cystic  contents,  394 
Cystin,  456 


Cystinuria,  456 

Daturin,  243 

Decoctions,  29 

Deliquescent  compounds,  303 

Density,  18,  73 

Dental  amalgam  alloys,  110 

caries,  373 

dies,  112 

enamel,  174 

porcelain,  174 

rubber,  197 

solders,  111 
Deodorants,  326 
Depressants,  354 
Derivation  of  metals,  89 
Dew-point,  26 
Dextrin,  226 
Dextrose,  229,  368,  376 
Diabetes  mellitus,  452 
Diacetic  acid,  368,  454 
Diaceturia,  454 
Diagnosis  of  non-urinary  diseases, 

478 

Dialysis,  11,  62 
Diamm,  240 
Diamond,  129 
Diastase,  251 
Diazo  compounds,  240 

reaction,  478 
Diet,  405 
Diffraction,  37 
Diffusion,  16 
Digestion,  396 
Digestive  fluids,  380 
Digitalin,  231 
Digitalis  poisoning,  349 
Dionin,  244 

Direct  combination  of  metals,  100 
Disinfectants,  326 
Distillation,  26 
Divisibility,  3 
Dog-bite,  364 
Double  refraction,  40 
Drinking-water,  311 
Dropsy,  403 
Drug  impurities,  325 
Drugs  and  urine,  427,  428 
Drying  oils,  220 
Ductility,  9 

Dynamic  electricity,  43 
Dynamo,  55 
Dyne,  50 
Dyspnea,  404 

Ear,  64 

Earthy  phosphates,  434,  465 


INDEX. 


515 


Ebullition,  27 

Edestin,  247 

Effects  of  heat,  30 

Effervescence,  299 

Efflorescent  compounds,  303 

Eggs,  408 

Ehrlich's  test  for  typhoid,  478 

Elaidin  test,  222 

Elasticity,  6,  9 

Elastins,  249,  371,  374,  408 

Elateriri,  234 

Electric  current,  48 

eel,  52 

heat,  56 

light,  56 
Electricity,  42 
Electrocauterization,  51 
Electrocution,  51 
Electrolysis,  50,  91 
Electrolytes,  61,  62,  83 
Electromagnetism,  54 
Electromotive  force,  48 
Electroplating,  50 
Electrotonus,  50 
Electrotyping,  50 
Eleidin,  249 

Elementary  analysis,  284 
Elements,  70 
Emetin,  244 
Emulsin,  251 
Emulsions,  29 
Enamel,  372 
Energy,  7,  401 
Enteroliths,  392 
Enzymes,  249,  251,  444 
Epilation,  51 
Epinephrin,  390 
Epithelia,  374,  472 
Equations,  85 
Eremacausis,  191 
Erepsin,  252,  381 
Ergot,  349,  361 
Erythrocytes,  376 
Esbach's  method,  449 
Esculin,  231 
Eserin,  244 
Essences,  29 
Essential  oils,  196,  348 
Ether,  32 

Ethereal  sulphates,  436 
Ethers,  208,  210,  329,  353 
Ethyl  chlorid,  203 

nitrite,  estimation,  283 
Eucalyptol,  329 
Euonymin,  234 
Europhen,  204 
Evaporation,  25,  305 


Exalgin,  239 
Excretions,  391 
Expansion,  16,  21 
Explosion,  299 
Extension,  2 
Extraction  of  metals,  91 
Exudates,  295 

Farad,  50 

Faradic  battery,  55 

Fat  in  urine,  456,  474 

Fats,  219,  408 

Fatty  acid  crystals,  464 

series,  192 
Feces,  391 

Fermentation  test,  452 
Ferments,  251 

Ferric  and  ferrous  compounds,  101 
Ferricyanids,  183 
Ferrocyanids,  183 
Ferrous  sulphate,  329 
Fibrin-ferment,  253 
Fibrinogen,  247 
Fibrins,  247,  378 
Fibrinuria,  429,  451 
Fibroin,  249 
Filariasis,  456 
Filters,  312,  313 
Fish,  407 

poisons,  350 
Fixed  oils,  219,  288 
Flame  tests,  273 
Fleitmann's  test,  280 
Flexibility,  10 
Flour,  321 
Fluorescence,  37 
Fluorids,  159 
Fluorin,  115 
Fluoroscopc,  55 
Food,  404 
Foot-pound,  7 
Force,  7 

Formaldehyd,  210,  329,  353 
Formalin  in  milk,  319 
Formamid,  238 
Formates,  180,  368 
Formic  acid,  213,  368 
Formulas,  77 
Fractional  crystallization,  60 

distillation,  27,  92 
Fraxin,  231 
Freezing  mixtures,  31 

-point,  22,  24 
Frictional  electricity,  43 
Fuchsin,  234 
Fulminates.  241 
Fusel  oil,  206 


516 


INDEX. 


Fusion-point  of  metals,  97 

Galactose,  230 
Galactotoxicons,  350 
Gallates,  179 
Gallic  acid,  218 
Gallotannic  acid,  217 
Galvanic  cell,  45,  46 

electricity,  45 
Game,  407 

Gaseous  irritants,  350 
Gases,  8 

of  body,  367 
Gas-formation,  279 
Gastric  absorption,  421 

juice,  381,  382,  418,  420 

motility,  421 

Gastro-intestinal  diseases,  480 
Gelatin,  249,  408 
Gelatinoids,  249 
General    rules    of    incompatibility, 

294 

Gentiopicrin,  231 
Glass,  174 
Gliadin,  249 
Globin,  247 
Globulins,  247 
Globulinuria,  446 
Glucosids,  230 
Glue,  249 
Glycerin,  207,  330 
Glycerophosphoric  acid,  208,  446 
Glycocholic  acid,  370 
Glycocoll,  239,  370 
Glycogen,  227,  368,  376 
Glycols,  207 
Glycoproteids,  248 
Glycosuria,  451 
Glycuronic  acid,  455 
Glycyrrhizin,  231 

Gmelin's  test  for  bile-pigment,  456 
Gold,  94 

refining,  287,  292 
Gonococcus,  476 
Granular  effervescing  salts,  217 
Granulated  metals,  95 
Granules  in  urine,  464 
Graphite,  129 
Gravimetric  methods,  273 
Gravitation,  4 
Gravity,  4 
Green  soap,  223 
Groups  of  metals,  107 
Guanin,  370 
Guaranin,  245 
Gum-resins,  198 
Gums,  227 


Gun-cotton,  226 
Gunpowder,  smokeless,  226 
Gutta-percha,  197 

Haines's     test  for  sugar,  452 
Hair,  374 
Halogens,  115 
Haloid  salts,  154 
Hardness,  8 
of  metals,  97 
of  water,  314 
Heat,  19 
Helium,  115 

Hellebore  poisoning,  349 
Helleborin,  231 
Hematin,  278 
Hematoidin,  379,  462 
Hematoporphyrin,  379 
Hematoxylin,  232 
Hematuria,  457,  471 
Hemic    and    circulatory    disorders, 

479 

Hemin,  378 

Hemlock  poisoning,  355 
Hemoglobins,  248,  378 
Hemoglobinuria,  458 
Hemolysins,  414 
Hepatic  lesions,  481 
Heroin,  243 
Heterolysins,  414 
Heteroxanthin,  370 
Hippuric  acid,  443,  463 
Histon,  247 
Histozym,  253 
Homatropin,  243,  282 
Horse-power,  7 
Human  body,  chemic  composition, 

366 

Hydatid  fluid,  395 
Hydrant- water,  310 
Hydrastin,  244 
Hydraulic  press,  12 
Hydrazins,  240 
Hydremia,  376 
Hydro-acids,  144 
Hydrocarbon  derivatives,  200 
Hydrocarbons,  191 
Hydrochloric  acid,  144,  382,  418 
Hydrocyanic    acid,    218,    281,    282, 

354 

Hydrogen,  113 
Hydrometer,  14 
Hydroquinone,  235 
Hydroxids,  151 
Hygrometer,  26 
Hyoscin,  243,  282 
Hyoscyamin,  243 


INDEX. 


517 


Hyoscyamus  poisoning,  352 
Hyperinosis,  370 
Hypinosis,  376 
Hypobromites,  158 
Hypochlorites,  157 
Hypophosphites,  165 
Hypostheniants,  354 
Hyposulphites,  165 
Hypoxanthin,  370 


Ice-water,  310 

Ichthyol,  236 

Ichthyotoxins,  350 

Ignatia,  356 

Images,  34 

Immunity,  412 

Impenetrability,  3 

Incandescence,  33 

Incompatibility,  2l>4 

Incubation  period,  412 

Indestructibility,  2 

Indican,  233,  368 

Indicanuria,  436,  465 

Indicators,  275 

Indigo  in  urine,  465 

Indol,  369 

Induction,  43 

Inertia,  7 

Infection,  412 

Infusions,  29 

inorganic  acids,  144 

Inosit,  368 
Inosituria,  453 

Intentional  incompatibility,  303 
Interference  of  sounds,  64 
Internal  secretions,  390 
Intestinal  bacteria,  398 

juice,  381,  385 
Intoxication,  412 
Inulin,  230 
Invertase,  252,  381 
Invertin,  252 
lodates,  159 
lodids,  158 
lodin,  118,  347 
lodism,  362 
lodoform,  204,  330 
lodol,  240 
Ions,  61 
Iridescence,  37 
Iron,  93 

poisoning,  347 
Irritants,  345 
Isoamylamin,  238 
Isocyanids,  241 
Isosulphocyanates,  241 


Jalapin,  231 
Jecorin,  368 

Kairin,  240 
Kaleidoscope,  34 
Keratins,  249,  408 
Kerosene,  194 
Ketones,  212 
Kiestein,  463 
Kjeldahl's  method,  439 

Lab-ferment,  253 

Labile  compounds,  72 

Laburnum,  349 

Lactates,  179 

Lactic  acid,  216,  330,  369,  419,  421, 

457 

Lactoscope,  423 
Lactose,  229,  368,  387,  424. 
Lactosuria,  453 
Lamp-black,  148 
Lanolin,  222 
Lard,  320 
Lardacein,  248 
Larynx,  65 
Latent  heat,  30 
Lathyrus,  349 
Laughing-gas,  139 
Lead  plaster,  224 

poisoning,  346,  3o7 

test,  282 

Lecith-albumins,  248 
Lecithins,  222,  368 
Legal's  test  for  aceton,  454 
Legumin,  247 
Lemon- juice,  411 
Lenses,  35 
Leptandrin,  231 
Leucin,  239,  369,  462 
Leucocytosis,  376 
Leucomains,  245 
Levulose,  229,  230 
Lieben's  test  for  aceton,  454 
Liebig's  test,  281 
Life,  401 
Light,  32 
Lightning,  45 
Lignin,  226 
Lime,  331 
Liniments.  223 
Lipaciduria,  457 
Lipase,  253 
Lipemia,  377 
Lipuria,  456 
Liquefaction,  25 

on  trituration,  302 
Liquid  air,  125 


518 


INDEX. 


Liquids,  8 
Liquor,  29 
Liquors,  206 
Lithernia,  411 
Lithium,  test,  282 
Litmus,  232 
Lobelia  poisoning,  355 
Lobelin,  242 
Loudness  of  sound,  63 
Lunar  caustic,  345 
Lymph,  389,  403 

Magnesium,  test,  281,  282 

Magnetic  poles,  53 

Magnetism,  53,  54 

Maize,  damaged,  362 

Malates,  180 

Malic  acid,  216 

Malleability,  9 

Maltase,  381 

Maltin,  251 

Maltose,  229 

Manganates,  172 

Mariotte's  law,  16 

Marsh's  test,  280 

Mayer's  solution,  277 

Meat-extracts,  408 

Meats,  321,  407 

Mechanic  equivalent  of  heat,  32 

Meconates,  181 

Meconium,  392 

Melanin,  374,  375,  455,  465 

Melanuria,  455 

Mendelejeff's  table,  86  * 

Mephitic  poisoning,  309 

Mercaptans,  236 

Mercuric  and  mercurous  salts,  112 

chlorid,  331 
Mercury  poisoning,  359 

test,  281 
Metabolism,  400 
Metal,  finding,  259 
Metalbumin,  394 
Metalloids,  113 
Metals,  89 

Metaphosphates,  170 
Methane,  193 
Methyl  chlorid,  203 
Methylene  blue,  331 
Metric  system,  2 
Mezcalin,  245 

Microchemic  tests,  281,  282 
Microchemistry  of  urine,  459 
Microscope,  35 
Milk,  319,  386,  407,  421 

-fat,  422 

poisons,  350 


Milk,  proteins,  424 
Milliamperemeter,  49 
Mineral  acids,  331,  343 

irritants,  345 

waters,  311 
Mirage,  35 
Mobility,  7 
Molasses,  322 
Molds  in  urine,  476 
Molecular  weight,  74,  285 
Molecules,  4,  77 
Momentum,  7 

Morphin,  243,  282,  351,  361 
Mucin,  248,  445 

bands,  466 
Mucoids,  248 
Mucus,  385 

cells  in  urine,  471 
Murexid  test,  442 
Muscarin,  352 
Muscle,  373 
Musical  scale,  64 
Mustard,  331 

-oils,  241 

Mycoderma  aceti,  253 
Myosin-ferment,  253 
Myosinogen,  247 
Myronic  acid,  231 
Myrosin,  252 

Nails,  374 
Naphtha,  194 
Naphthalene,  199,  331 
Naphtols,  236 
Narcotics,  350 
Narcotin,  243 
Natural  gas,  195 

waters,  309 

Nephritides,  differentiation,  477 
Nerve-substance,  374 
Nervous  diseases,  482 
Nesslerizing,  315 
Neurin,  370 
Neurokeratin,  249 
Neurolemma,  374 
Neurotics,  350 
Nicol  prism,  40 
Nicotin,  242,  355 
Nitrates,  160,  317,  345 
Nitrifying  ferments,  254 
Nitrils,  241 
Nitrites,  161,  317 
Nitro-acids,  149 
Nitrobenzene,  236,  354 
Nitrocelluloses,  226 
Nitrogen,  124 
Nitroglycerin,  209 


INDEX. 


519 


Nitrometry,  282 
Nitroprussids,  183 

Nitro-salts,  159 

Nomenclature,  79 

Normal  constituents  of  urine,  434 

serum,  413 

solutions,  275,  276,  277 
Noxious  trades,  309 
Nucleins,  248,  370 
Nucleoproteids,  248 
Nuts,  409 
>,ux  vomica,  356 

Odor  of  urine,  428 

Ohm,  49 

O'idhtm  albieans,  253 

Oleates,  179 

Olefins,  195 

Oleic  acid,  215 

Oleomargarin,  221,  320 

Oleoresins,  198 

Oliguria,  431 

Oliver's  test  for  bile-salts,  445 

Opera-glass,  35 

Ophthalmoscope,  36 

Opium  group,  243 

poisoning,  351,  361 
Oppler-Boas  bacilli,  420 
Orellin,  233 
Organic  acids,  213,  368 

acid  salts,  176 

matter  in  water,  315 
Osmazome,  407 
Osmosis,  lls  61,  403 
Ossein,  249,  371 
Osseous  diseases,  481 
Oxalates,  176 

Oxalic  acid,  216,  282,  344,  369 
Oxaluria,  444 
Oxidation,  77,  305 
Oxidimetry,  278 
Oxids,  131 
Oxybutyria,  454 
Oxybutyric  acid,  368,  454 
Oxydases,  252 
Oxygen,  119,  331 
Oxyhemoglobin,  378 
Ozone,  121,  332 

Pancreatic  juice,  381,  385 

lesions,  481 
Papain,  251 
I'apaverin,  243 
Paracasein,  247 
Paraffin,  194 
Paraffins,  192 


Paralbumin,  246 

Paraldehyd,  211 

Parasites  in  urine,  474 

Paraxanthin,  370 

Pectin,  227 

Pellotin,  245 

Pepsin,  252,  381,  419 

Peptonized  foods,  408 

Peptons,  248 

Peptonuria,  449 

Perchlorates,  157 

Periodic  law,  87 

Peronin,  244 

Peroxid  of  hydrogen,  332 

Petroleum,  193,  332 

Pharmaceutic  assays,  283 

Phenacetin,  237 

Phenazone,  240 

Phenol-phthalein,  236 

Phenols,  235,  345,  369 

Phenyl-anilin,  230 

Phenyl-hydrazin,  240 

Phenylic  acid,  235 

Phloridzin,  231 

Phonograph,  65 

Phosphates,  168,  315,  367,  406 

Phosphaturia,   428,   430,   434,   435, 

465 

Phosphids,  170 
Phosphin,  127 
Phosphites,  170 
Phosphorescence,  33 
Phosphoric  acid,  150 
Phosphoms,  126,  348,  360 

test,  281 

Phospho-salts,  1(58 
Photography,  38 
Photogravure,  50 
Phototherapy,  38 
Phthalein  group,  234 
Physic  properties  of  metals,  95 
Physics,  1 

Physiologic   and  pathologic   chem- 
istry, 366 

properties  of  metals,  103 
Physostigma  poisoning,  356 
Physostigmin,  244 
Phytolaccin,  234 
Pialyn,  253,  381 
Picnometer,  14 
Picric  acid,  236,  324 
Picrotoxin,  234,  357 
Pilocarpin,  244 
Piperazin,  238 
Piperin,  244 
Pitch,  64 
Platinum,  95 


520 


INDEX. 


Plumage  pigments,  380 

Poisonous  bites  and  stings,  363 
metals,  in  water,  318 
reactions,  300 

Poisons  and  urine,  483 

Polarimeter,  41 

Polariscope,  41 

Polariscopy,  42 

Polarity,  74 

Polarization,  40 

Polyuria,  431 

Populin,  232 

Porcelain,  174 

Porosity,  5 

Post-mortem  examinations,  339 

Potable  water,  309 

Potassium  permanganate,  332 
salts  poisoning,  347 
test,  282 

Practical    physic    and    chemic    in- 
compatibility as   applied  to 
medicine,  298 
Precipitate,  84 
Predigested  foods,  408 
Prescriptions,  303 
Pressure  of  atmosphere.   17,  18 
of  liquids,  11 
on  immersed  bodies,  12 
Prism,  35 
Propeptons,  247 
Propionic  acid,  215,  369 
Protagon,  68 
Proteids,  248 
Proteins,  246 

of  urine,  450 
Proteoses,  247 
Prothrombin,  377 
Protoplasm,  371,  401 
Pmssic  acid,  354 
Pseudocasts,  470 
Pseudopepsin,  381 
Ptomains,  245,  459 
Ptyalin,  252,  381 
Purdy's  test  for  sugar,  453 
Purification  of  water,  312 
Purin,  370 

bodies,  369,  441 
Putrefying  ferments,  254 
Putrescin,  238 
Pyridins,  240 
Pyrocatechin,  235 
Pyrogallin,  235 
Pyrology,  269 
Pyrophosphates,  169 
Pyroxylin,  226 
Pyrrol,  240 
Pyuria,  458,  470 


Qualitative  analysis,  256 
Quality  of  sound,  64 
Quantitative  analysis,  273 
Quantity  of  urine,  43  i 
Quassin,  234 
Quercitrin,  232 
Quinidin,  243 
Quinin,  243,  282,  332 
Quinolin,  240 

Radiation,  20 

Radical,  finding,  263 

Radicals,  77 

Radiometer,  33 

Raoult's  law,  23 

Rasmussen's  test  for  bile-pigments, 

456 
Reaction,  83 

of  degeneration,  51 

of  urine,  430 
Reactions  of  water,  314 
Reagent,  84 

Red  blood-cells  in  urine,  471 
Reduction,  77,  92,  305 
Refining  of  gold,  287,  292 
Reflection,  34 
Refraction,  34 
Reinsch's  test,  280 
Rennin,  253,  381,  420 
Resins,  198,  348 
Resorcin,  235,  333 
Respiration,  403 
Respiratory  diseases,  480 
Retention  of  urine,  432 
Rigor  mortis,  369,  373 
Roasting,  92 

Roberts's  test  for  albumin,  448 
Roentgen  rays,  55 
Rosanilin,  234 
Rosin,  198 
Rosolic  acid,  234 
Ruberythric  acid,  233 
Ruhmkorff  induction-coil,  54 

Saccharin,  238,  322 
Saccharose,  227 
Saffranin,  233 
Salicin,  232 
Salicylates,  181 
Salicylic  acid,  217,  319,  333 
Saliva,  381,  382 
Salivary  calculi,  382 
Salol,  210,  333 
Salophen,  210 
Salt,  406 
Salts,  82,  154 
separation,  268 


INDEX. 


521 


Sanitary  analysis  of  water,  313 

chemistry,  307 
Santalin,  233 
Santonin,  232,  356 
Saponin,  232 
Sarcin,  370 
Sarcolactic  acid,  369 
Sarcolemma,  373 
Sausage,  321,  349 
Scale  compounds,  102 
Scammonin,  232 
Sciagraphy,  55 
Scillitin,  232 
Scopolamin,  243 
Sea-water,  311 
Sebum,  386 
Secondary  current,  55 
Secretions,  380,  403 
Sediments  in  urine,  429,  459 
Selenium,  123 
Seminal  fluid,  388 
Sericin,  249 
Serpentaria,  234 
Sewer-gas  poisoning,  353 
Silicates,  173 
Silicon,  128 
Silver,  92 

nitrate,  333 

poisoning,  360 
Simon's  test,  281 
Sinalbin,  232 
Sinusoidal  currents,  52 
Skatol,  369 
Skin  affections,  482 
Smegma,  386 
Snake-bite,  363,  414 
Soaps,  222,  333 
Sodium,  test,  282 
Solanaceae,  242 
Solanin,  232,  243 
Solanum,  3.') 2 
Solids,  8 

Solubility  of  medicinal  salts,  acids, 
and  bases,  295 

of  metals,  99 
Solution,  28,  29 
Sound,  63 
Sources  of  heat,  19 

of  light,  33,  34 

of  metals,  90 
Spartein,  242 
Special  incompatibility,  300 

methods  and  apparatus,  279 
Specific  gravity,  5,  13,  15 
of  metals,  97 
of  urine,  432 

heat,  24,  74 


Specific  infection,  478 

Spectra,  39,  40 

Spectroscope,  38,  380 

Spermatozoa,  388,  444 

Spermin,  388 

Spheric  aberration,  38 

Spiegler's  test  for  albumin,  448 

Spigelin,  242 

Spirit-level,  12 

Spirits,  206,  324 

Spongin,  249 

Sputum,  394 

Stabile  compounds,  72 

Standard  solutions,  275 

Stannates,  173 

Starch,  226,  408 

Starvation,  402 

Static  electricity,  43 

Steapsin,  2o3,  381 

Stearates,  180 

Stearoptens,  197 

Stercobilinuria,  456 

Stereoscope,  36 

Stoechiometry,  85 

Stoneware,  74 

Stools,  391 

Storage  battery,  47 

Stramonium,  352 

Strontium,  test,  282 

Strophanthin,  232 

Strychnin,  244,  282,  356 

Sublimation,  27,  92 

Succinates,  180 

Succinic  acid,  216 

Sucrose,  227 

Sugar,  adulterations,  322 

in  urine,  451 
Sugars,  detection,  289 
Sulphates,  162,  337 

in  urine,  436 
Sulphids,  161 
Sulphites,  164 
Sulphocarbolates,  181 
Sulphocarbolic  acid,  236 
Sulphocarbonates,  168 
Sulphocyanids,  182 
Sulphonal,  237 
Sulphur,  121 
Sulphuric  acid,  147 
Sulphurous  acid,  148,  333 
Suppression  of  urine,  431 
Suprarenal  extracts,  390 
Surgical  conditions,  483 
Symbols,  70 
Sympathetic  ink,  102 
Synaptase,  251 
Synovial  fluid,  390 


522 


INDEX. 


Synthesis,  189 

Syrup,  29 

Systems  of  crystals,  58 

Tannates,  179 
Tannic  acid,  333 
Tannins,  217,  232 
Tartar  of  teeth,  373 
Tartaric  acid,  216 
Tartrates,  177 
Taurin,  370 
Taurocholic  acid,  370 
Tea,  323,  362,  410 
Tears,  385 
Teeth,  372 
Telegraph,  57 
Telephone,  56 
Telescope,  35 
Tellurium,  123 
Temperature,  21 
Tenacity,  9 

of  metals,  98 
Tension,  48 
Terpenes,  196 
Test-metals,  418 
Thallin,  240 
Thebaicum  group,  243 
Thebain,  243 
Thein,  245 

Theobromin,  245,  370 
Thermal  unit,  31 
Thermo-electricity,  52 
Thermometers,  21 
Thio-acids,  146 
Thio-salts,  161 
Thiosulphates,  165 
Thymol,  334 
Thyroidin,  390 
Tin  chlorid  poisoning,  347 
Toad-stool  poisoning,  352 
Tobacco,  324,  355,  360 
Total  solids  of  water,  314 
Toxicology,  336 
Toxins,  245,  412 
Transparency  of  urine,  433 
Transudates,  395 
Trichloracetic  acid,  215 
Trional,  237 

Triple  phosphate  crystals,  463 
Trituration,  chemic  decomposition, 

302 

Trypsin,  252,  381 
Tube-casts,  465 
Tubercle  bacilli,  414,  425,  476 
Tungstates,  173 
Tuning-fork,  65 
Turpentine,  196,  334 


Tyrosin,  239,  369,  462 
Tyrotoxicon,  350 

Ultimate  analysis,  284 
Ultramarine,  176 
Urates,  460,  461,  464,  469 
Urea,  238,  369,  391,  437 
Urease,  254 
Ureometer,  439 
Uric  acid,  370,  441,  460,  461 
Urinary  calculi,  483 

casts,  465 

crystals,  460 

parasites,  474 

sediments,  429 

tumors,  474 
Urine,  391,  425 
Urinometer,  432 
Urobilin,  426,  445 
Urochrom,  426,  445 
Uroerythrin,  446 
Uroroseinogen,  446 
Urotropin,  238,  334 
Uses  of  metals,  104 

Valence,  75 
Valerianates,  177 
Valeric  acid,  215,  369 
Vapor,  25 
Vaselin,  194 
Vegetable  acids,  344 

foods,  408 

irritants,  348 
Velocity,  7 

of  electricity,  52 

of  light,  34 

of  sound,  63 
Veratrin,  244 
Vernix  caseosa,  386 
Victor  Meyer  apparatus,  285 
Vinegar,  322,  334 
Viscera,  375 

Visceral  degeneration,  375 
Viscosity,  10 
Vital  electricity,  52 
Vitellin,  248 
Volatile  oils,  196 
Volatilization  tests,  272 
Volt,  48 

Volumetric  methods,  275 
Vomit,  393 

Water,  131,  309,  366,  406 
-gas,  194,  353 
incompatibilities  of,  302 
of  crystallization,  60 
sanitary  analysis,  313 


INDEX. 


523 


Watt,  50 

Weber,  49 

Weight,  5 

Wells,  310 

Williamson's  test  for  sugar,  453 

Wines,  206,  323 

Wood-silk,  226 

-spirit,  205 
Woorara,  356 
Work,  7 

Xanthin,  370 


Xanthorhamnin,  233 
X-rays,  55 
Xylonite,  226 

Yeast,  253,  420,  476 
Yew,  349 

Zein,  247 

Zinc  sulphate  poisoning,  347 

Zincates,  173 

Zymase,  252 

Zymogens,  380 


UNIVERSITY  OP  CALIFORNIA  MEDICAL  SCHOOL  LIBRARY 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


1919 


NGV  1  4  1923 


1931 


DEC 


1931 


QD31  Hill,  E.G. 

H55    (PQ-gp-book  of  Chemistry. 

1903 


4751 


JAM  18  1919  *™ 


I.WIWPRQITY  Of  PAIIFORNIA  MEDICAL  SCHOOL  LIBRARY 


